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Tuesday, September 8, 2009

Dodge Transmission Output Speed Sensor


Rear Differential Speed Sensor above is mistakenly replaced because of a code for the Transmission Output Speed Sensor in the pictures below.



Top and Side View of Transmission Output Speed Sensor and installed on Left Side of Transmission Tail-shaft.

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This is another inside baseball type post concerning auto and truck repair. The first picture is of the Rear Differential Speed Sensor which is mistakenly replaced because of a code involving the Transmission Output Speed Sensor located in the left side bottom of the transmission tail-shaft. The three pictures below the one of the Differential Speed Sensor are of the Transmission Output Speed Sensor and location on a 1999 Dodge Ram 1500 pickup truck with 3.9L engine and three speed automatic transmission without overdrive. It came in with a check engine light on and intermittent stalling when slowing from freeway speeds into traffic. The code was straight forward – PO720 – Output Speed Sensor Circuit. The dealer stocks six of these. They are a common failure item. I am doing this post because the speed sensor on the differential in the first picture is often mistakenly replaced for the Transmission Output Speed Sensor code. Replacing the one on the rear differential will not get rid of the code or the problem.
I have had a number of Do It Yourself customers change the wrong speed sensor after getting a free code read at a parts store. This is mostly for their benefit because I don’t get any laughs out of people parts changing the wrong part on their vehicle, especially in these tough times. The Transmission Output Speed Sensor number on this particular vehicle and many others in the late nineties and early 2000’s is Mopar #04800879. They are not all the same so removing the sensor on the affected vehicle and jotting down the number is the best course to follow.

NOTE: Here's a quick diagnostic check for major problems or governor transducer and wiring faults. I won't explain where any of the ports are because each person attempting this check should have the proper equipment, safety cautions, and manuals:
 
For checking a transmission similar to the one mentioned in the above post to tell if the problem is in the transmission or the wiring is to put a pressure gauge on the governor port and start the motor. You then pull the case connector and put the transmission in drive. You should see main line pressure and the transmission should go into 3rd gear. If you see no pressure then you know that the problem is in the unit and the transmission needs replaced. If you have pressure and the transmission goes to 3rd gear then you have to look at the wiring and governor valves.
That’s all for this update, but if you’re appreciative of the information, here is a link to my Author's Page on Amazon with all my novels listed. Thank You! Every little bit helps my writing gig. :)


371 comments:

1 – 200 of 371   Newer›   Newest»
Charles Gramlich said...

I believe you were speaking English here, but I am going to run it through one of those translation software programs anyway. ;)

BernardL said...

Yep, Charles, a picture is worth a thousand words but if you've never seen the underside of a 1999 Dodge Ram 1500 pickup even the pictures won't help. :)

RRobinson said...

My 99 Dodge 2500 Ram won't accelerate..transmission is NOT slipping, and just brought it home from a tune up. Top speed right now is between 20 & 30 mph, speedometer seems to work...are these symptoms of a bad speed sensor located on the transmission? If so...how do you release the wiring and then remove the sensor? Please & thank you!

BernardL said...

RR - If the engine revs but the vehicle doesn't speed up then the trans is slipping. If you hit the gas and you don't feel a miss but there is a low throaty sound to the exhaust it may be your 99 Dodge has plugged up catalytic converters. The speed sensor will set a code and cause intermittent stalling but I've not seen it cause power loss as you describe. Guessing, I would say plugged cats, especially if you took it in for a tuneup because it was missing. Misfires will melt the insides of the cats and cause blockage. Remember... I'm guessing. You need to have it checked professionally.

amber said...

Sometimes my 99 Dodge 2500 Ram won't shift out of first, when this happens I stop take the battery cable off and put it back on then it will shift.This leads me to believe it may be the transmission speed sensor or something else eletronic.Is it a sensor? And Where is said sensor on my truck?

BernardL said...

Amber, you need to take your Dodge in to a professional for diagnostic work. It's impossible for me to answer your question in an Internet post. It seems you have an electronics problem but every time you disconnect the battery you also erase any computer codes that might help with the diagnosis.

Susan said...

Dear BernardL. Thank you, thank you, THANK YOU!!!!! I used your excellent photos and information to order the transmission output speed sensor, verify it was the correct part, and to find the sensor under the truck (1999 Dodge RAM 2500 diesel). Changing it out was even easier than I expected. The only unexpected things were that NO transmission fluid leaked out and that I had to use my code reader to reset the check engine light...it did not go out after changing the sensor.

BernardL said...

In the position where it's mounted, Susan, there would not be any fluid leakage. The computer has to see the correct values from the sensor for a number of starts before it will turn out the light. It will not happen immediately. I hope the sensor corrects your problem. Thanks for posting.

Susan said...

Took the truck for a test drive and all the problems are gone. Thank you again.

BernardL said...

That's good news, Susan. Thanks for the update.

jessegonzo said...

my speedometer drops down to zero when get uder 20mph and reads normal speed when i get over 20mph??? is this the output speed sensor???

BernardL said...

It's possible. This particular sensor usually causes a code to set and the check engine light to come on, JG. I advise you to have the vehicle diagnosed rather than guess at the problem.

BernardL said...

Anon. Take your vehicle in to a reputable shop and have it checked out and repaired correctly. Do it soon before you ruin the transmission. That's my advice.

BernardL said...

Think about it, msklmk. How can I know from here. If you didn't switch out the exact same engine and trans from the exact same year vehicle with all the same accessories then you're in trouble and it's not possible for me to help you from the Internet anyway. If you switched the exact same, then a reputable shop should be able to help you out with a diagnosis, but they'll need the vehicle in their shop to do it, and no, it will not be free.

BernardL said...

I tried to give you good advice msklmk but since you want magic instead, here's some for you. I just made your posts disappear. Pretty good, huh?

Big D said...

Hi BernardL, Got a 99 Dodge 1500 4wd 5.2... Check eng light came on tran won't get out of 1st gear.. Code reads Output speed senor.. Will Speed Senor make tranny do that????

Big D said...

Also speedometer stop working

BernardL said...

If the computer sees no signal at all from the output speed sensor it can affect everything, Big D. If you're doing this yourself, I'm sure you've checked the fluid level. If you replace the output speed sensor and the problem remains, you'll have to have it checked professionally. They had a lot of trouble with the governor solenoid and transducer on those transmissions too. You could also have a hard failure where there may be pieces of servo in the pan. The sensor is an inexpensive logical place to start if you want to try something.

Big D said...

Thank You....

Shawn said...

I has a 99 jeep GC Laredo with a 4.0 automatic.
On deceleration around 2000 rpms the engine revs up to 2200-2400max.
Is this a cause of a bad Trans Output shaft Sensor?
It's been doing this for quite some time now and killing my brakes.

BernardL said...

You'll need to have it diagnosed, Shawn. This post was to differentiate between the output sensor on the trans and the sensor on the rear end. The one on the transmission causes a PO720 code not the one on the rear end. Sudden revving of the engine while decelerating is dangerous. You should not put off having it checked. There's no way for me to diagnose your vehicle from here on the Internet. Your Jeep and the Dodge 1500 in my post do not have the same transmission.

Anonymous said...

I have a 1994 Dodge Intrepid 3.3, and it runs beautifully ...for a while. Once it warms up it still runs and shifts great till i come to a stop it then locks into Limp mode and wont come out of second gear. Cycling the power will restore normal operation however, put it neutral and turn the car off and back on and its perfect again till i stop. I'd would love to hear suggestions on this my theory is the output sensor but I have not the means to get it tested at present.

BernardL said...

I doubt it's the output sensor on that one, Anon. It might be the solenoid pack for the trans. You need to take it in to a shop and explain exactly what it's doing. Diagnostic steps can't be skipped.

john said...

I have a 2001 1500 ram pickup could the speed sencer couse tranny to drop gears at highway speeds? There is no slipping at all just jumping gears. Also tried manuely putting but staid in first

BernardL said...

As in the last post, John, you can't skip diagnostic steps. I have to assume you've checked fluid levels, tire pressures, and made sure the brakes aren't locking up. If everything else seems okay, the next step is to check for computer codes for the transmission which could point you in the general area of the trouble. If there are no codes, I would take it into a transmission shop to get it checked out. Every Output Sensor I've had come in the shop that was bad, set a code. You can try changing it and see if it helps. They're not that expensive and they're easy to change.

Anonymous said...

HELLO, I HAVE A 1994 RAM 1500 AND IT JUST TAKES ALITTLE LONGER TO SHIFT FROM 2ND TO 3RD GEAR AND WHEN I HIT THE OVERDRIVE OFF BUTTON IT SOUNDS LIKE ITS REALLY WINDING OUT. IS THIS A SENSOR PROBLEM OR DO YOU HAVE ANY IDEAS. MUCH APPRECIATED THANKS,MIKE

BernardL said...

The Output Speed Sensor normally sets a code, Mike. It seems you may be having problems with the governor solenoid or transducer, which I've mentioned in other comments. You should have it serviced professionally to see if anything inside the pan may be an indicator of trans failure.

flagear said...

I have a 2006 dodge 3500 4 speed auto trans. The transmission started to stick in in first gear. The check engine light came on, but showed no code at autozone this sat.4-30-11.It has been running fine and the check engine light even cleared itself yesterday.Today it did it again. Once i got it in second it was fine shifting on my way home. Could this be the output speed sensor going bad? Thanks

BernardL said...

I don't think so, flagear, although if the output sensor stops working it can cause a whole host of problems - but it usually sets a code. As in some of the other comments, they've had a lot of trouble with the governor solenoid or transducer on those. You can try the OP sensor if you want to gamble on a cheap fix. If that doesn't correct your problem though you'll need to take it in to a shop for diagnosis.

Brandon said...

Bernard... very impressive that you would take the time to address theses Issues.
I have been doing a lot of searching and I have come up with one thing this is different from all others... no check engine light.
1999 Dodge Ram 2500 V10, will go into 1st and 2nd, wont shift into 3rd. Spedo stopped working few months ago, unless I am going 85 mph, then it works fine... but still no check engine light. I supposed I can try replacing the solenoids on the tranny, then if that doesnt work take it to a shop. Just curious if you have any other ideas.
Thanks in advance

BernardL said...

Rather than throw parts at it, Brandon, I'd advise taking it in for a check now. There is always a chance something could go wrong with what you're gambling with, making the cost of repair much more expensive. The speedometer problem could be related to either the rear wheel sensor or the output sensor on the transmission as in the blog, although they normally set a code.

flagear said...

Thanks BernardL, I removed the round plug by the linkage on the trans.which kept it in third gear so i could limp it to the dealer where i purchased an output speed sensor and it fixed the problem. I appreciate your help!

BernardL said...

That's great news, flagear. I haven't run across one with your symptoms being the OP sensor. Thanks for the update. I'm sure it will help someone else out.

flagear said...

The problem came back on Fri. It wasn't the OP Senor. The check engine light came on once again no code. I put a Govoner Solonid and a Pressure Sensor Switch in it and that was the problem.The check engine light cleard itself this weekend.It is even shifting better from 1st to 2nd now. Thanks again !

BernardL said...

Thanks for the update, Flagear. If the computer cleared the code itself, that's a very good sign.

Karen said...

Thank you for your time. Your information pertaining to the output speed sensor was extremely on a 99 dodge was very helpful, You saved me a lot of time and money. 15 dollars was a lot better than looking at a tyranny replacement. Thank you again.

BernardL said...

You're welcome, Karen. I'm glad the sensor fixed your problem.

Anonymous said...

I know your post refers to a RAM.. I have a 99 dodge intrepid 2.7 liter engine. The other day I was driving and all of a sudden my speedometer stopped working and then it would only stay in gears above 2nd. So it wouldn't go into first gear and then 3 minutes later my check engine light came on I did the key dance nd it gave me code p0700 and I did a little research about my input and output speed sensors but do u know where they are located and how do I change them?

BernardL said...

Both the input and output sensors on your vehicle are on the side of the transaxle, anon. If you insist on changing them without a detailed manual the only thing I can suggest is purchase them from the dealer and find them by comparison. Otherwise, please take it in to a shop to have them do it because with that code I believe you're on the right track with replacing them.

wllmleith said...

I have a 1997 Dodge Ram 1500 with a 5.9L instead of the stock 5.2L. It is a amazing truck but since I drove it last it wont go into any automatically unless I do it manually. I have asked Dodge and my dad is a mechanic but nobody can tell me what is wrong. It acts like the bands aren't holding the gears in place but I'm not sure if thats the problem. I can shift it manually thru the gears and it does fine but if I try to let it do it itself it's like the overdrive is stuck engaged while thru every gear. I have 2 spare transmissions but I don't want to tear them down in order to repair the stock. Do you have any idea what it could be? It wont shift into any gear but 3rd in automatic.

BernardL said...

wllmleith, as you may have read, they've had a lot of trouble with the governor pressure solenoid and the transducer on those transmissions with shift problems. The only way to find out for sure is to take it into a good trans shop for diagnosis. It's impossible for me to do anything but guess.

~Ashley~ said...

i have a 2001 dodge ram 1500 and the ABS light and emergencey brake light turned on and wont go off also at the same time the speedometer started going crazy and just bounces all over the place (no way of telling how fast im going) We were told it was the rear differential speed sensor which we changed out (twice thinnking the first one might of been a dud) but it didnt fix the problem. Could this be one of those missdiagnoses for the Transmission Output Speed Sensor? Thanks in advance for your help

BernardL said...

It could, Ashley, but you need to find out what codes are being set, especially in reference to the ABS system.

Siddharth said...

BernardL, thanks for all your advice on this post. it helped in figuring out the problem for me.

My Dodge Neon 2005 though is giving this problem repeatedly (P0700,P0720,P0731). 2 days back when it went into the limp mode with the above error codes, I got the input output sensors replaced. I drove it for 1 day and it drove well. However, it came back in the limp mode with the speedometer going crazy, engine light on again. I got a replacement for the sensors. The replacements didn't last even for 5 minutes and gave out during the test drive itself.
So, 3 sets gone in a matter of 3 days. Does it look like a wiring issue to you or is there is a more serious problem lurking with the TCM? I will really appreciate your advice on this.

BernardL said...

Sid, that does seem like a wiring problem. You're going to need to do continuity checks at the sensor wiring harness connectors. I'd start with the Output Speed Sensor.

Dan said...

Bernard,

My 2006 Dodge Ram 1500, 5.7l Hemi has issues. My speedometer does not work and the lights on the dash have lite up like fireworks. The code from the scanner say U1120? The vehicle has stalled several times when I have needed to break suddenly from moderate speeds. I am told the code mean lost wheel distance....what do I replace to prevent me from spending an arm and a leg at the dealership? Military here and need to get this fixed before I deploy. Don't want to have the wife deal with this mess. Thanks!

Jana said...

Hi I have a 04 Dodge Stratus 2.4. When I start out driving it does fine then once I stop at a red light or slow down to turn, Its like the tranny gets stuck and wont shift out of 1st gear it will go but wont shift and the RPMs keep going up to fast I try to drive it. Hoping its not nothing major. Thanks

BernardL said...

I'm sorry, Dan, but you may have to take it in for professional diagnosis. An output speed sensor can cause the speedometer problem and stalling. If you still have the original battery, and it's having problems, that can cause a lot of strange instrument cluster problems.

The 2004 - 2006 Dodge Durango had a recall on the instrument cluster for the U1120 code and assorted lights and outages in the cluster but not the 1500. Sorry, but other than what I've just written I can't give you any specifics without much more scanner data and diagnosis.

BernardL said...

Jana, as you've probably read in other comments, it's impossible for me to determine what's wrong with your vehicle over the Internet. You could have anything from a sticking valve in the valve body to a plugged up torque converter. The solenoid pack could be at fault or the filter plugged. You need to take it in for a professional diagnosis.

Austinj19 said...

hello bernardl, i recently purchased a 1999 dodge ram 1500 4x4 5.9l, everything seemed fine when i test drove it but i got it to the interstate to head home and then it wouldnt go above 40 mph and the rpms were at 4k, had it towed home and this morning i went out to start it up and then it wouldnt idle and now it does not turn on. I ordered a IAC for that but with the transmission im stumped, im going to try replacing the filter and draining it an re-filling with ATF. Is it possible it could be the Output Speed Sensor? when we dropped the truck off at my house i took it up the road just to see and it shifted fine but now nothing.

BernardL said...

Austin, normally when you hit the gas and the engine revs without the vehicle moving faster it means something has gone wrong hydraulically. I think you're going at it the right way. I'd wager the filter is plugged. If I'm right, you'll need to make sure the cooler lines get flushed out too. I don't know that it will do you any good though, but you have to start some where. Unfortunately, the next step is another transmission. I don't think the speed sensor would cause the symptoms you're experiencing.

Anonymous said...

I have a 2001 2500 diesel long bed. When I gradually accelerate through the 45 to 50 mph zone my truck surges repeatedly like ugh ugh ugh. If I accelerate rather quickly up to 55mph I don't have this problem. Any ideas?

BernardL said...

It could be anything without a basic diagnostic check, Anon. The injection pump may be failing or any number of things. You need to get it checked for codes, scanner data, fuel quality and pressure, etc.

Anonymous said...

I have a dodge ram 1500, 1999, 4x4, 5.9l. I took it to autozone, they did a computer test and said the problem was the speed sensor. I replaced the speed sensor, but my check engine light didn't go off. took truck back to autozone they ran another scan and acused the same problem speed sensor, the guy at autozone told me that since I had replaced the speed sensor it could be some ground wire. can you help me at all? ha, also sometimes it won't shift from 1st gear. could it all be related? thank you in advance.

BernardL said...

Anon, did you even read this post and look at the pictures? Did you have the same code as the one listed in the post where people have been changing the wrong speed sensor?

Anonymous said...

Bernard thankyou for doing what you do, You helped me and you are helping a lot people. Yes I got the right output speed sensor and my check engine light is gone, I took it to the state inspection to get my sticker, but the guy said although my check engine light isn't on anymore, I have to drive for a while because the computer has not reseted itself yet. I had first replaced the sensor in the rear and it sure did work, by replacing the sensor in front light went off. but replace the sensor on the back was the sales man idea based on what he read on the computer car thing there. I went to a different place ran another computer check and this time the right sensor was given to me, and it was just like the ones you show the pics.
Thank you very much for you help.
tough economic time and you helped saving some money thanks again...
Good bless you..

BernardL said...

You're very welcome, Anon. I'm glad it worked out for you. Thanks for the update.

Myrna said...

Bernard, I left an Anon posting about the 2001 2500 deisel that chugs between 45 & 50mph. If the check engine light isn't on will a diagnostic machine still pull a code and does Auto Zone or someplace similar have the proper machine to diagnose without the check engine light coming on?

Myrna said...

Bernard, I left an Anon posting about the 2001 2500 deisel that chugs between 45 & 50mph. If the check engine light isn't on will a diagnostic machine still pull a code and does Auto Zone or someplace similar have the proper machine to diagnose without the check engine light coming on?

BernardL said...

Myrna, this is not a blog concerning diesel engined Dodges. It was specifically for a screw-up with a certain code being set but the wrong speed sensor being replaced. Yes, the code will be in memory even though the light is not on - if any code was set. Any guessing about these vehicles, even with a code checker can be very expensive. Is there some reason you don't want a professional to check your vehicle out for a proper diagnosis?

Anonymous said...

Bernard, We have a 2000 dodge 1/2 ton pickup that is shutting off when it is stopped at lights. Had a professional code read it. He said it had a false reading and cleared the light. This truck sat all winter without being drove but it was doing this before the winter. We thought our grandson drove it too low on gas and got dirt and water in the tank. At first it would not start but now it runs. At first badly but now better. It stalled yesterday a lot and the code light came back on it reads speed sensor, can that be.

BernardL said...

It sure can, Anon. The lady who owned the Dodge in this post had intermittent stalling problems too. Old gas can really cause a lot of weird problems too.

Hunter said...

Hey I have a 1999 dodge ram laramie slt and my transmission slips around first and 2nd gear and also sometimes when i stop it does not want to go until you press hard on the gas to get it moving could this be in the sensors?

BernardL said...

It's impossible to say, Hunter, without scan data and basic checks on fluid levels, grounds, and power connections. This post concerned the wrong speed sensor being diagnosed as causing the speed sensor code listed in my post. You can try it if you want and gamble. They're not that expensive or hard to replace but I have no idea whether it will cure your problem. If you've read the other posts, you can see they've had other problems with the governor and solenoid pack.

Anonymous said...

Hello Bernard. I was reading your post to see if anyone had the same problem as I do. I have a 2000 Ram 4x4 and my rpm's will go to 3000 before shifting into second but once into high gear it runs fine it also stops hard when you stop like the brakes are locked but this only happens when you first start it in the morning after the first stop everything is fine with the brakes too. I'm a little tight oin funds and was hopeing I could correct this myself. The auto parts store said they could not check this for me because i do not have any lights on stating there is a problem. Do you have any idea as to what it could be? Thank you in advance for your time.

BernardL said...

Anon, if you've read the other posts you know they've had trouble with the governor pressure transducer that could cause your harsh upshift along with a bunch of other things. Whether your funds are short or not, you'll have to have it checked out.

ChrisMAC said...

1999 Dodge 3/4 v10. The spedo quit working and the ABS light and Brake light remain lit. All fuses ok and everything else seems to be working ok. No engine or tranny issues either. Speed op sensor???

BernardL said...

Yes, Chris, a speed sensor can cause a speedometer problem and abs light. Without scanner data and codes, you'll be guessing.

ChrisMAC said...

Bernard-
Thanks for your quick response!! I will get it scanned today and go from there. You are helping a lot of people!! Thank you for that!

Anonymous said...

Bernard:
I have a '99 ram 2500 diesel that has stopped dropping into low gear under 25mph. If I stop at a light it will eventually shift down. Problem then repeats itself. All fluid levels are fine.

Any thoughts? - Terry

Anonymous said...

I have a 2000 Dodge Durango 5.2L, and while on a trip thought i had gotten some bad gas. After a fill up, 30 mins, started stalling when i slowed to a stop. Made it home and drained the tank, and put fresh gas in. Still doing it. Talked to a mechanic and they told me that the fuel pump need to be replaced, did so. Still have problem, but now will not shift out of 1st gear. Went to another shop and they tried to pull codes, there were none, for the engine or trans. They had it hooked up with it running put it into gear and it stalled, nothing showed on their computers. They have no clue.

BernardL said...

Terry, my guess would be the governor transducer or solenoid, but a blockage of fluid flow can also cause it. You need a professional to check codes and data along with dropping the pan to see if you have a lot of debris floating around in there. Also the cooler lines or cooler can get blocked up.

Anon, your Durango problem seems like a torque converter locking up due to a blockage too. If there's a lot of debris in the pan, it would point to plate material or metal stopping the fluid flow. If I were you, I'd take it to a different shop that does transmission work. The Output Sensor does set a code as in my post example.

BC78 said...

My 2003 Dodge ram 1500 4x4 5.9 lt
has started shifting funny and sometimes like it just drops into neutral.The speedometer is jumping all around the engine light is on and the ABS and brake light are on.I did have it scanned and it said it was the output shaft speed sensor. But the ABS and brake light indicators is what is throwing me for a loop. Just wondering if you think it could also be the variable speed sensor. Thanks for your time.

BernardL said...

BC78, the output sensor can cause many unrelated problems. I would change it first, but at the same time I would check for power and ground connection corrosion and corrosion at the ABS module connectors.

Robob69 said...

I have a 98 Dodge Ram 1500 4X4 sport with 5.9 360.
How do I know what Transmission I have in it?
46ER,47RE,48RE????

I am having issues shifting from 1st to 2nd only at 3000 RPM and I seen you told someone that it is the Governor Regulator and I am looking for one and they want to know what tranny I have... I have no clue..

BernardL said...

VIN number through the dealer, which is where you should be buying any part you're gambling on a fix without a diagnostic check, Robob69.

Anonymous said...

Hi Bernard

I have a 2001 dodge ram 1500 5.9L. My speedometer and odomter work fine. However while driving my truck while start to shift funny and my abs and brake light will come on. I noticed that it only shifts wierd while I give it just enouph throttle to maintain my current speed. If I give it no throttle or enouph to accelerate its fine. My light when scanned says its the rear wheel speed sensor. I brought it to a mechanic and had it replaced. It still did this. I brought it back and they found a break in the wire and then fixed that. Still does this. I brought it back and they can find nothing. Im at a complete loss now and I have no idea what to do next. Any idead?

Thanks

BernardL said...

Anon, did you read this post with pictures? Yours could be the exact problem I made this post about. Your mechanic may have changed the wrong sensor. The output speed sensor is the one on the transmission not the differential.

Anonymous said...

My mechanic actually just replaced the entire transmission w a remanned tranny and about a month afterwards replaced the sensor again on the transmission and the rear wheel speed sensor.

BernardL said...

It's strange you would leave that info out of your first post, Anon. Take it back to the mechanic who replaced the tranny until it's fixed.

djmixer272 said...

I have a 1999 Dodge Ram 1500 3.9L. Last night after leaving a friends, my truck wouldn't shift out of first gear, reving the engine up to about 3,000 rpm's. I stopped to get something to eat for about 15 minutes, came back out, and it was fine. This morning on my way to work, same thing. I pulled over to the side of the road, shut the truck off for 5 minutes. Started it back up and it was fine. Can it be the speed sensor? Check engine light was already on for a different symptom. My IAC (idle air control) sensor needs to be replaced.

BernardL said...

Without scanner data it’s impossible for me to say, dj. It’s more likely you have a problem with the solenoid pack or governor pressure transducer that have been mentioned in the comments many times. They will cause harsh up-shifts as can a plugged filter. I wish I could tell you the output speed sensor was causing your problem, but it would normally set a code.

djmixer272 said...

Thank you for the response. Funny thing happened to today. As mentioned in my previous post, my check engine light was on due to a faulty IAC (idle air control sensor)so today I figured I'd at least fix that problem and get that out of the way. Now my truck doesn't have a problem with shifting, BUT......... it still seems sluggish taking off from a stand still, and the rpm's are racing at almost 2000rpm's when parked. Going down the road is fine, but as soon as I slow down I can feel the truck wanting to keep going because of the rpm's. Was the IAC problem one in the same with the transmission, and is this rpm problem a symptom as well of the transmission? I am so confused now as to what's going on. Not to make it worse or more confusing, but I thought I'd add this in here just in case it's all part of the problem.....my fuel gauge stopped working right around the same time my truck wouldn't shift out of first. I guess it's time to get rid of this thing.

BernardL said...

DJ, you might consider having the truck diagnosed professionally rather than scrapping it. When you replaced the IAC did you use an OEM part or aftermarket? It's no coincidence when the RPM's suddenly stay up after you replace a part relating to idle. The fuel gauge can be anything from a cluster problem to a bad sender to a poor connection to a bad PCM. The computer may be receiving the correct signal from the sender but not interpreting it correctly.

djmixer272 said...

Ok, I'm going to stop by a garage on the way home today to see if they can diagnose it. I did all I could as a "do it yourselfer". Thanks for your input. It's nice to find a place online that I can ask questions.

Anonymous said...

bernard as well as many other ppl i to have th same problems 1994 5.9l 47re shifts great 1-3 but tranny will not shift into OD any thoughts?

BernardL said...

Anon, that's too little info for me to even make an intelligent guess. A bad throttle position sensor can cause the computer not to allow overdrive, but that's a shot in the dark. It would be best for you to have it diagnosed by a professional. Your vehicle is five years older than the one I posted about here originally. No, they're not all the same.

Anonymous said...

I have a 2002 dodge Ram 1500 4wd, like many posts I too had the ABS, Brake, Air Bag & check engine lights and lost my speedometer all at the same time. It coded P 0500. I changed out the speed sensor on the rear differential test drove it, after some miles the speedometer started working and all the lights went out except the check engine light. As I was backing into my driveway they all came back on again, drove forward, lost the speedometer again too. Still coded P 0500, Did I change the wrong sensor? If it is possible to be the one on the tranny? I could not find anything that resembles the one in your pictures. Can you help?

BernardL said...

Yes, Anon, it could be the one on the transmission. The reason the pictures in this post may not seem familiar is it's a 1999 2WD Ram 1500 truck. If you decide to do it yourself, you will have to get an OEM manual, or ask the dealer parts guy to show you an illustration when you buy the sensor. The lights blinking may or may not be related to the PO500 code and sensor. You may be having a problem with the dash itself or loose power or ground connections. The instrument cluster assembly has been a problem on those.

chesterdixon said...

BernardL, I have a 1998 dodge dakota sport with a 3.9l v6. The transmission will shift to 2nd gear but then it goes right back down to 1st. I work for honda and tried to scan for codes but our snap on scanner says it cant communicate with the transmission. i was wondering if a faulty speed sensor would possibly cause my shifting problems.

BernardL said...

It's a cheap gamble to try it, Chester, but shift problems as you describe usually have to do with another problem Dodge has on those transmissions - the inner lip seals on the direct clutch drum. They include updated seals in the rebuild kit but overhauling it may be your only option.

chesterdixon said...

i have never rebuilt a domestic transmission, but have rebuilt some hondas using the manuals. Would this be something i could possibly do or is much more complecated?

chesterdixon said...

Or do you think it be better bet just to buy the parts and let my local trans shop do the labor

BernardL said...

Chester, let the local trans specialist deal with it. They can confirm the need for the rebuild too.

chesterdixon said...

ok i was wondering if it was a sensor because my abs light, brake light are on and also my speedo doesnt work would the rear diff sensor also cause shifting problems

BernardL said...

Chester, it would not be the rear differential sensor as this post was originally about. If you're going to replace an output speed sensor, replace the transmission output speed sensor.

JoeD said...

Bernard,
My son has a Dodge Durango, V8, 4.3l AWD, 2003 (estimate year). When starting out you have to manually put the shifter in 1st gear and once you gain speed shift to drive. It will then operate under all conditions normally until you come to a complete (or almost complete) stop. Then you must shift back to 1st and start the process again. Can you tell me what part in the transmission is the most likely cause (shift solenoid, pressure transducer etc.). It has been this way for a while and has not gotten any worse. Appears not to be the transmission proper as far as I can tell, seems more like a sensor issue.
thanks for your advice

BernardL said...

JoeD, I'd need a lot more information than that to even make a guess. I'm assuming it's a 4.7L engine. My advice is to have a transmission place diagnose it. If the pan is full of debris it's probably trashed, especially if the trans oil and filter have never been serviced. It should have set a code at some time with the problem you've described.

Mike garcia said...

Hi my name is mike just got a 94 dodge ram and the tranny doesn't like to down shift after I slow down or stop the guy I bought it from said a freind rebilt the trann for him and thats y it shifts like it does is this true or do you think it might be a sensor or a bad tranny

BernardL said...

No, that's not true, Mike, but it's impossible for me to know the cause other than I doubt it's any sensor. If the governor sticks it can affect downshifting. You'll have to take it in to a trans shop for diagnosis.

Anonymous said...

I can't get that rear sensor to go flush. Tried tightening the nut, but still lacks a quarter inch. Don't know if I should force it. Tried shifting thru gears with no help. There's gotta be a trick to get that thing to sit flush. Any advice would be greatly appreciated. And thanks for doing what you do.

BernardL said...

No, Anon, you should not force it. Did you try your old one to see if it would go in still? Did you buy an OEM replacement or an aftermarket sensor? If you bought an aftermarket sensor and your old sensor pops right in then you need to get an OEM replacement.

Anonymous said...

I have a Dodge Ram truck the automatic transmission does not shift well out of 1st. I can get it to shift by putting it in neutral sometimes. I replace the transmission but it did not correct the problem. What else could it be. I have no Check engine lights.

BernardL said...

I'm sorry, Anon, but that's so little information I couldn't even guess at the cause. My advice is to have it checked out at a shop.

Teri said...

I have a 1999 dodge 2500 V10 8.0L. It all of a sudden wouldn't go into park and then next day started not to shift unless you let off the gas. Is it probably the transmission going out. Didn't know cause of the not going into park. There are no check engine lights or nothing.

BernardL said...

Yes, Teri, I think you have a major transmission problem. Dodge has had multiple problems with symptoms resembling yours because of governor, transducer, and valve body problems with the check balls and seals. All you can do is take it in for diagnosis and be ready for bad news.

John said...

Have been reading you blog with a great deal of interest. I have a 1999 Dodge Dakota Sport 2.5L stick (4+od)that is throwing a P0500 code and the speed-O doesn't work. I don't see a transmission speed detector on the transmission tail shaft. There are two sensors I can see, crank shaft position (forward of clutch slave)and a neutral detector switch on the right side of the tranny. No other wires go to the tranny. Installed an OEM differential speed detector with no change in the problem. You said in many other posts that the instrument cluster could cause this problem. Since this must not be an isolated occurrence, and not asking you to be Karnack from the Johnny Carson show, what would be on the list of things you would look at first? I have access to an O-scope and other high tech goodies. What I don't have is a wiring diagram that would let me do point-to-point tracing. Although driving down the road with the dash in my lap while I probe points isn't on my things to do list. I know jack stands, just being funny.

BernardL said...

John, the VSS should be on the transfer case on a 4wd. You didn't mention whether you had any ABS codes to go along with it, but you replaced the sensor that usually causes ABS and VSS codes. I hope you're putting in OEM sensors. I hope the one on the transfer case fixes it for you. If it doesn't you may have to have it diagnosed at a shop. Check closely for any sign of problems with the harness and connections.

John said...

Not a 4wheel drive, it is a stick 5 speed (4+overdrive). I've run my hands over the entire trans case and the only two sensors are the ones I mentioned earlier. The speed-O has never worked right, only coming on at 25mph or so, then showing the correct speed. Now it doesn't work at all. What is the typical failure under the dash that causes this type of problem? Did the Einsteins at Dodge run the signal to the computer through the speed-O to save a buck?

BernardL said...

John, you need to have it checked out then. You can't check it out with a code reader. You have to be able to read data to see where the signal is being disrupted. If scanner data shows signal normal to body control computer and PCM then the likely problem would be a cluster fault or a bad connection, or in some cases a faulty PCM. I can't go any further with you on guessing.

John said...

Yea, I'm kind of at my wits end on this one. I'm going to spend a couple of hours tomorrow making sure all the plugs & associated wires under the dash are tight and no broken ground wires. Then it will be off to the shop and let someone with the right book run the problem down. Guessing on a problem like this is a no-win situation. Thanks for you help, keep on doing what you are doing...

BULL said...

2004 Ram 2500 quad 5.9 DSL 197,000 miles no issues with trans took for flush work good for about 100 mile then starting shifting funny took back they sent me to transmition shop they drop pan changed fluids, filter now it will not shift into O/D no code on computer, shops said it need a rebuild trans. does this sound right or am I getting taken

BernardL said...

Bull, that happens many times with high mileage vehicles that have not had regular transmission oil and filter changes. When one is finally done, it sometimes triggers a failure, which is why many shops are hesitant about servicing a high mileage vehicle's transmission when regular service has not been performed. I think your trans oil and filter change was just the last straw for your transmission. Even if you have serviced it regularly, nearly 200,000 miles is a long time and they are not indestructible, so no, I don't think you're getting taken. The change may have triggered the failure but I doubt it was the cause.

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Chester Dixon said...

hey bernard i wrote while ago about my truck shifting from first to second and then back down to first. the abs light and brake light were also on. i replaced all my sensors in the trans and the rearend and thats when i found that the pins inside the connector for the rearend sensor had seperated from the two wires so i bypassed the conector and its working just fine. best $600 truck ive ever owned plus another $50 for sensors.

BernardL said...

Thanks for the update, Chester. Yep, frayed or worn connectors can cause a myriad of strange problems. I'm glad it worked out for you.

Anonymous said...

Hey Bernard....I have a 2000 doge ram 1500 with the 5.2- I was burning about 5 quarts of oil a month so i figure the engine is gone? It also is extremely slow and will get stuck at about 50 and just gets louder without getting faster.Transmission AND Cat?

BernardL said...

Anon, pumping that much oil through the exhaust can definitely take out the cat. To confirm it you can take a pressure reading in front of the cat. I have a fitting I made up from an old oxygen sensor to screw in and take a pressure reading, or you can drill your own port in front of the cat and plug it later. You can also drop the exhaust to confirm but that's not for the faint of heart running around with that kind of noise. :) You may be having governor/transducer problems or if the engines revving but not increasing speed, the converter might be toast too. The most likely though is a plugged cat.

BernardL said...

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BernardL said...

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David Ostrander said...

I have a 96 doge 1500 5.2l with a rebuilt trany out of a 97 the guy i bought it from replaced the output spped sensor and claims the when he did he fried the insturment cluster. i replaced the cluster and it all works but the speedo the orginal reason y it was not working i have replace both the sensors on the difer. and the output and still nothing i also replace rwal box under the dash and the speedo again just in case now im lost and almost broke any ideas.

BernardL said...

I can't pinpoint your problem for you, Dave, but I can give you a couple ideas. If you replaced the correct speed sensor on the transmission and the cluster was rebuilt correctly, then you may have a problem in the wiring harness between the speed sensor and cluster. I would start out by checking for obvious frayed harness spots such as where they run under the battery and the connector at the sensor itself. To get in deeper, you'll need a wiring diagram for checking continuity between harness points. If the speedometer has never worked since that transmission was replaced your problem may even be an internal problem in the transmission. You also didn't state whether you've had codes checked or not.

David Ostrander said...

yes i had the code checked only o2 and batt temp came up

BernardL said...

Dave, the battery temperature sensor shares a ground with a number of other sensors and the transmission solenoid assembly. It's located under the battery tray. If you can't find anything obvious with frayed harness or connectors, and replacing the battery temp sensor doesn't help, you'll have to take it in for a diagnosis. You may have some trouble finding the battery temp sensor. Try the dealer first.

David Ostrander said...

ok here is where im at i have gone over all the wiring for the speedo. The wiring for the output speed sensor runs straight to the PCM the green and black wire is showing 2.5v and the blue and black is 2.5 v also. From what the wire digram is saying the blue and black wire is sopose to be ground. Now the ABS sensor rear whel speed sensor in the rearend is showing about 6v to the red wire and 0.04 to the black wire. And the white and orange VSS signal wire that runs from the PCM to the speedo is showing 6.5v. no wire breaks trace all the wires 100%. Im kinda leaning towords the pcm having issues with grounding looking to maybe changing the pcm.

David Ostrander said...

Also i have found the problem with the batt temp sensor the wires were fraied taped the off no more code lol.

BernardL said...

You're on the right track, Dave. What you did with the frayed wire section might have a lot to do with the speedo problem. I know you've checked the wiring, but I still think you need to take a closer look at the wiring because of the shared ground between the trans solenoid pack and the battery temperature sensor. I'd open that harness up until I was sure of all grounds in the engine compartment and to the computer. Otherwise, you may be right about the PCM.

Anonymous said...

I have a 2005 4x4 ram 1500, 5.7 hemi, A/T, coming to stop in drive it stalls. Coming to stop in neutral it does not stall. I read in the above postings it could be the transmission speed sensor. I'm not sure which senor that is? I looked around the tail shaft and do not see it. (I was going by the picture posted above). There is a small sensor on top of the rear transfer case that has a small ball bearing inside of it, not sure what that is. Please help! Rod

BernardL said...

Rod, the above pictures are from a 2WD 1999 1500. It is not the same as yours at all. Also, the 1999 set a code PO720 for the Output Speed Sensor. You have not mentioned having your vehicle checked out for codes. Stalling can happen for a variety of reasons completely unrelated to the transmission. You will need to find out if the vehicle is setting any codes and on a 2005 'Mode 6' scanner data can be accessed which can give much more detailed info into misfires and sensor malfunctions.

Anonymous said...

Sorry Bernard should have included more info… 6 months ago while traveling had chk eng light come on, stopped for lunch and when I tried to leave the tranny went into limp mode. Had engine light checked at auto zone that happened to be next door to where I just had lunch, came out as transmission error. Took the printout with me. Went to a local shop and gave them the error codes (which I didn’t get back from them) was told it needed a transmission oil change and sump filter(s). Made it home with no problem. 3 month ago chk eng light again, took to Dodge dealer they found it was an EGR it was replaced by them. And they also flashed the ECU with an update. The stalling started out hit and miss when coming to a stop but now has progressed to an every time occurrence. I did an experiment, stopping in gear, STALL. Shifting into natural before stopping NO STALL. At this point I’m going to take it to the dealer. Thanks for the help any way! Rod

BernardL said...

The dealer will be able to access the more in depth Mode 6 data. Shifting it to neutral may be an indicator of trans problems, but it also changes the idling rpm. Anything, including a tank of low quality fuel can cause a stalling problem if there are no codes.

Mike C said...

Bernard,
I have an 03 Dodge 1500 SLT it is having a problem shifting. The problem only happens when the temp drops below 50 degrees. it shifts from 1st to 2nd fine. when it goes to shift into 3rd it will shift but then drops back into 2nd gear. I let up off the gas and then it shifts back into 3rd. As soon as I touch the gas it will be fine for a minute then starts the routine all over again. I am currently stationed in Germany and we really don't have any mechanics over here that can tell me what is going on. I bought a code reader from Craftsman but it doesn't show anything wrong. can you help?

BernardL said...

Mike, they've had problems with the governor pressure solenoid and sensor on those, but you would still need to find a shop to test it or replace it. If there are a lot of miles on it, and you have not serviced the transmission regularly, it may be going out. You didn't mention if you've ever done a trans oil and filter change on it.

Anonymous said...

Bernard, I have an interesting problem with my 1999 Dodge Ram 1500 4x4 5.9. First, I ran it through several large puddles of water, probably not smart. But the light did not go on at all that day. Today, I started the truck and my 4WD light stays on. One interesting note though, I took the truck up on the freeway because of a low battery issue to charge it and I was very low on gas, like less than 3 gallons. The amazing thing is that the 4wd light flickered then went off. I continued to drive it, until I filled the tank with gas. Now the light is back on and burning bright again and no flickers at all, I even took it back up on the freeway but it did not go out. Can you figure out what the problem is?

BernardL said...

Anon, first make sure you have a good battery in it. Secondly, they've had problems with transfer case motors on those, but you can't just guess at it. You need to take it into a shop for diagnosis.

Greg said...

Thanks I am one of those that replaced the speed sensor in the differential. I now have the correct part and will attempt to replace it. I hope it is easy!

BernardL said...

I hope it fixes your problem, Greg.

Jack said...

My 99 2500 RAM cummins diesel slips in and out of overdrive between 45-50 mph. Below and above this speed, there are no problems. Could this be a transmission speed sensor?

BernardL said...

Without scanner and code data, it's impossible for me to know, Jack. A likely suspect would be the torque converter clutch solenoid, but it could be any of the speed sensors causing feedback. They've also had a number of computer reflashes dealing with that problem.

Victor Principe said...

Bernard, Want to thank you for posting so much good info. I have one for you. I have a 1999 Dodge Ram 2500 automatic, Cummins. Here are the symptoms: 1. At highway cruising speed the ABS and Brake light come on. This does not happen in city driving. Only above 55MPH. 2. The overdrive will button no longer disengages the OD. If I push it a bunch of times the OD might disengage, but rarely. 3. Towing a 4000LB trailer up 8% grade the truck will not pull. Put the pedal to the floor to maintain speed (50MPH). RPMS will fluctuate by about 500 RPMs when this happens.
I have replaced both the Rear Differential Speed Sensor and the Transmission Output Speed Sensor but no change. Any thoughts

BernardL said...

Victor, read my comment right above yours to Jack. He has the same problem, and once again I can't tell you anything from the Internet without data and codes other than what I wrote to him.

javis said...

I have a 2002 gmc yukon and it seems like the rpm revs up a lil before shifting from 2nd to 3rd and the check engine light just came on. Is this something i should seriously be concerned about?

BernardL said...

Yes, Javis, you should be concerned. Have your Yukon checked out. With a sudden engine rev while under load, your engine could be damaged in addition to the transmission. The check engine light is not to be ignored.

tony777 said...

i have a 2001 dodge ram 1500 v6
just bought cheap!
when i give it gas?
tranny feels like its jumping when i take off from stop if i take off easy real easy doesnt do it
but i know its maybe some kind of sensor?? could it that speed sencor
or another

oh motor and tranny were rebuilt back in may 2011

any help ?

thanks

tony

BernardL said...

Impossible to say without diagnostic data, Tony. It's possible you have a bad engine or transmission mount or even an ignition miss. Your description of the problem would be fine if you were explaining it to a tech getting ready to check it out in person. From the Internet, I have no way to help you without data.

tony777 said...

thanks bernard !

i replace the tps today and the
iac hoping that was it
but no dice it is better?
runs idles steady at the light now

alot better but still dying when i put it in reverse starts right back up and so i paid 900 for it
but i like it she was neglected
so im going to put a cap on it
at $800 and see how she turns out

thanks bernard

tony

oh ! motor and tranny was rebuilt
back in may 2011

BernardL said...

Are you sure you don't just have a tank of bad gas, Tony? If it's been sitting around neglected, maybe the gas is old an low quality. What $800 cap are you talking about?

tony777 said...

$800

is what i plan to spend on it
it fells like i have a major vacum leak?
i check the hoses from booster to manifold
then passenger side lines as well cant find any leaks going check it today again real good
its dying in reverse
had auto zone do a free code check
yesterday a

then she printed a recipt
this is what it said
aa fuel trim bank one condition
aa sensor to calculate the air/fuel ratio of the engine the computer has recognized a rich or lean condition on one egine back
only / left bank
if one bank and two codes set together suspect fuel presure or maf( mass air fuel)sensor oxygen sensor defective
ignition misfire repair fuel injection problem.

??

thanks tony !

tony777 said...

the code ?
was po171 .

thank you

BernardL said...

PO171 is a code for bank 1, sensor 1, too lean. Some possible causes are - the sensor may be bad, or you have a vacuum leak, or the electric fuel pump may be going out. Have you done a fuel pressure check? The fuel filter and strainer are built into the fuel pump module. Pressure should be in the 60 PSI range. If you have to replace either the sensor or the fuel pump module assembly, use only OEM. It may be time for you to quit guessing and take your truck into a professional shop before you blow the $800 dollars without a fix, Tony.

Anonymous said...

Hi Bernard, I have a 2005 Ram 1500 V8 4.7L and recently started having problems. While cruising over 50 mph, very erratic tach and jerking. Throwing a code of P0068. Just bought a throttle position sensor and going to replace this weekend. Am I headed in the right direction?

BernardL said...

Yes, Anon, I believe you're doing the right thing changing the TPS. They are a common failure on that particular one. I hope you're going with an OEM replacement.

ZebJones said...

Bernard ,Thanks for all of the good info. My son has a 99 Dodge 2500 v10 that won't shift out of first gear unless he lets off of the gas ,then it shifts right in. I replaced the output speed sensor,fluid and filter but didn't help. Could it be the govenor? If so where is it ?I'm assuming pulling the pan you can access it. Thanks Oh, by the way it has no codes.

BernardL said...

My advice, Zeb, is get an OEM manual or have a professional do the repair. It very well could be the Governor/Transducer, but you'll be guessing. Here's a YouTube video probably similar to yours.

http://www.youtube.com/watch?v=Gb24f8mWCB8

Anonymous said...

I have a 2007 dodge ram 3500 wit the 5.9 engine. My speedometer and odometer doesn't work and my engine, ABS, and brake light is on. Could this be the speed output sensor on my transmission??

BernardL said...

Anon, without code and scanner data I can't even give you an educated guess. A fellow tech on my iATN network said it is probably an ABS module problem, depending on the codes retrieved. You need to take it in to a dealer for a diagnostic check.

Liberty Story said...

Please help Bernard! I have a 1999 Dodge Durango 4x4 5.2 ltr. My ABS and brake light came on and my speedometer jumped around over 70mph. My husband changed the ABS append sensor on the rear differential and now not only are the ABS and brake lights on but my speedometer doesn't work at all and my odometer is lit up but doesn't add miles. Also, my gas gauge is jumping around so I have to listen to the low fuel chimes every thirty seconds......any ideas what this may be?

BernardL said...

I can only make an educated guess without any code or scanner information, Liberty. If the speedometer stopped completely after your husband replaced the speed sensor in the differential, he either got a bad aftermarket one, a wrong one, or the wire harness connector is bad. I would put the old one back in and see if the speedo starts working again. If it does, I would advise buying an OEM replacement sensor. The dash acting up might be a bad solder joint on the dash itself, or your fuel sending module in the tank may be going out. For now, I would stick with the problem that started when the differential speed sensor was replaced. I'm sorry, but that's all I can give you without data.

Liberty said...

I appreciate your help. I am taking it to Advanced Automotive to have them read the codes. Thanks again.

Liberty Story said...

So I took my Durango to AA and when they hooked it up to the computer all it said was speed sensor sooo I bought the speed sensor that goes on the back of the transmission. My husband replaced it and noticed a broken wire. He fixed the wire and now my speedometer, gas gauge and odometer work but the brake and abs light come on after driving a very short distance and my check engine light is still on. I am so frustrated....and tired of spending money on parts that are not broke. Should I have it hooked to a computer again?

BernardL said...

No, Liberty, if you're tired of guessing, you should take it into a professional shop and get it fixed. Why didn't you let the place you call Advanced Automotive diagnose and fix your vehicle? If you wish to keep guessing then going back to get the codes read is your only other option. You have still ignored my question as to whether you're using OEM parts or aftermarket, and you still have not mentioned the codes found. I will answer your questions by e-mail only after this. My post here was for people mixing up which sensor to change when they get a code PO720.

minneSNOWtan said...

Hi Bernard, I read through a lot of your post and my problem is similar but has the folks at the Dodge dealership stumped. I have a 98.5 Dodge Ram 2500 with the 5.9 24v and an automatic transmission. About a week ago I was pulling a 5th wheel trailer and came to a stop light. When the light turned green and I went to drive away the truck stalled out and died. I restarted the truck but my ABS and Brake light were on and the truck wouldn't shift out of first gear. Fortunately I was only a couple of blocks from the Dodge dealership so I pulled in there and they couldn't pull any codes. They did a reset to the computer and it shifted fine and has since until tonight. Tonight I drove through a pretty deep puddle and my ABS light and Brake light came on and again my truck won't shift out of first but on top of that the speedometer quit working too. If you have any advice it would be greatly appreciated since the dealership here doesn't seem to know where to start looking. Oh...the ATF is full and the color is good, no signs of heat or burning fluid.

minneSNOWtan said...

Oh...I'm out in the sticks in Montana now so I don't have a lot of mechanic options...

elijah haynes said...

203 dodge ram 1500 jump are come out
of gear after 400mph of driveing
on a trip get off the gas go back on
for about 35 miles do the same out of
Gear. this only happen when on a trip,

BernardL said...

Minne, my only guess if the dealer hasn't found any indication of codes or data indicating a problem is that they've had a lot of trouble with the governor solenoid or transducer on those. I'm sorry, but it's not possible for me to give you much more. Also going over the wiring carefully, especially near the speed sensor connector is another place to check.

BernardL said...

Elijah, without more information, I can't even guess what's wrong with yours. You need to have it checked out at a professional shop.

HossV11 said...

Hey bernard read your blog helped me replace the proper sensor. now that i replaced the proper sensor it drove good for a couple of days now seems to hesitate around 20 mph and dont seem to go over 40 mph without fluttering and if i give it a lot of gas it wont even rev high. could this be do to the speed sensor in the rear? This is my work truck hoping you could help me out with this. let me know if you need anymore info. 99 dodge durango 5.9 2wd.

BernardL said...

Hoss, you have to have the basics checked out first - scanner and code data, power and ground connections, ignition, fuel pressure, compression, and if you have plugged catalytic converters. I'm sorry, but when someone drives into my shop with a problem like yours, I have to check the basics first.

Donna said...

Bernard, can the problem with the speed sensor be on a 2006 dodge 2500 diesel turbo as well? Because it takes forever to shift from first to second but works fine after it gets out of first.

BernardL said...

Donna, you need to have it checked out by a reputable shop with a scanner capable of reading 'Mode 6' data along with codes. It's impossible for me to even venture a guess without data. Dodge is still having trouble with the Governor Pressure Transducer on those, but you can't guess at it or parts change until you switch the right part. That will get expensive.

Donna said...

Ok, thanks, I am still going to try the output speed sensor first as it's only $44 and I can do it myself. A friend of mine had the same problem(just found out)and was told to change this sensor. However I did not know about the transducer and will keep that in mind :)

BernardL said...

Well, I hope it's the sensor, Donna. Good luck.

Donna said...

lol, you and me both :)

Eva n said...

Mr. Bernard, my vehicle has quite a few problems. It has stalled as you talked about first in your blog, and the speedometer quit working. It also has the code you mentioned. I replaced the output shaft speed sensor with two different parts just to make sure that there weren't bad parts. But neither fixed my problems. My gauge panel is fine as well. I have abs light, brake light, no speedo, the check engine light, and the seatbelt light will also not extinguish.

BernardL said...

Eva, you don't mention year, make, model, or whether your vehicle is 2wd or 4wd, manual or automatic transmission, gas engine or diesel.

Assuming it is a model like the one in my post, possible problems could be: wiring harness and connector problems, the speed sensor on the differential could also be bad which would account for the speedo not working, you may have replaced the part with two different aftermarket sensors when you should have replaced it with one OEM sensor from the dealer, and you may have a problem in the dash itself.

jdeutscher said...

I've got a 99 ram 1500 with 5.2L and right now all I've got is 1st and reverse. It's done this to me in the past and I've replaced the rear abs sensor and disconnected the battery left it for 20mins reconnected it and it was fine. I've tried that again and this time it didn't work. What else should I try?

BernardL said...

JD, without scanner data, codes, or basic diagnostics on the transmission, it's impossible for me to give you anything other than a guess. If you've read the other comments, they've had a lot of trouble with the governor pressure transducer and solenoid. Here's the basic diagnostic procedure, but if you don't have a pressure gauge and factory manual, then you need to have a transmission place do it for you. They could drop the pan after the initial tests to see if it's full of debris. All precautions for putting a vehicle in drive have to be followed, which is why I don't give instructions to people doing this in their backyard. If you put your vehicle into drive without proper precautions you will probably end up on someone's Darwin Awards List.

For checking a transmission like you have the way to tell if the problem is in the trans or the wiring is to put a pressure gauge on the governor port and start the motor. You then pull the case connector and put the trans in drive. You should see main line pressure and the trans should go into 3rd gear. If you see no pressure then you know that the problem is in the unit and the transmission needs replaced. If you have pressure and the trans goes to 3rd gear then you have to look at the wiring and governor valves.

Anonymous said...

I just replaced the output speed sensor on my 1998 Durango. I just tightened until it felt snug as the old one came out easily. Is there a torque spec. on the sensor? Thanks.

BernardL said...

Anon, NO torque spec. It's an o-ring seal and it's plastic, so as long as it's not loose, you should be fine.

Anonymous said...

I have a 1999 Dodge Ram 1500 Laramie, with a rebuilt transmission. I am female and know nothing about vehicles at all...when driving 60 mph it runs at 4000 rpm's is that normal? Also my 4 wd just all of a sudden stopped working on the day we get a blizzard...any idea why or what it could be (or how much the cost might be to fix it) or if it is even fixable? Thanks!

BernardL said...

Anon, you need to take it back to the shop that rebuilt the transmission. No, it's not normal, and it's impossible for me to give you a clue as to what's wrong without any scanner and code data. If you don't take it in to a professional shop you may damage the rebuilt transmission beyond repair.

Anonymous said...

I have a 2001 dodge ram 1500. My transmission slips in 3rd gear. I have replaced the governor sensor/solenoid, park/neutral safety switch. Would the speed sensor cause it to slip. And everyonce and awhile it slips in 1st and 2nd but not very often. The fluid level is correct with the correct type of fluid. Any ideas?

BernardL said...

I don't think so, Anon, but without scanner data it's impossible for me to say. A speed sensor actually causing a slip would most likely set a code. I'm sorry, but I would recommend taking it to a shop and have the scan done and pan dropped to look for debris.

Anonymous said...

I have dropped the pan several times and there is no debris the fluid is spotless. Nothing around the magnet in the pan. I do need to get a scanner on it. I was thinking about getting the bands agjusted..but this is all a guess. I am very mechanical but on a transmission its kinda learn as i go. Thank you for the post back though.

BernardL said...

Without a pressure gauge check with scanner data, you're shooting in the dark, Anon. These clunkers are mechanical, but with so much electronic data available, sometimes you just have to take it in to a shop with the tools to check it.

Ramiro Vera said...

hey i been having some trouble with my 1996 dodge ram 1500. It'll rev up fine but it wont shift out of first gear. i scanned and it came up with the code PO720 which is the output speed sensor so i switched it out and im still having the same problem. i been looking around online and i had found somewhere where it said that the output sensor can cause all of the systems my truck is having but nothing changed. P.S My Speedometer doesnt move from ZERO at all..

BernardL said...

Ramiro, I don't think you've read any of the other comments so I'll repeat this one. Here's the basic test in one with a no shift problem. You may have to have it done at a shop.

For checking a transmission like you have the way to tell if the problem is in the trans or the wiring is to put a pressure gauge on the governor port and start the motor. You then pull the case connector and put the trans in drive. You should see main line pressure and the trans should go into 3rd gear. If you see no pressure then you know that the problem is in the unit and the transmission needs replaced. If you have pressure and the trans goes to 3rd gear then you have to look at the wiring and governor valves.

Ramiro Vera said...

I have had the transmission checked and everything turns out fine. Also the catalyc converter is making a really bad rattling noise. could all the problems be because of the cat?

BernardL said...

Ramiro, no you have not had it checked out, because if it won't shift out of first, then something is wrong. Even if the catalytic converter was plugged up, it couldn't keep the transmission from shifting out of first gear. They've had a lot of trouble with the governor solenoid or transducer on those. Doing the proper tests at a shop is the only way you're going to find out what's wrong.

Ramiro Vera said...

Im Taking It To A Shop That Specializes On Transmissions And Ill Post What The Results Of That Were.

BernardL said...

Thanks, Ramiro. An update will help others. Sometimes, there's nothing you can do without professional help, and guessing can get very expensive.

Ramiro Vera said...

Hey It Truned Out To Be A Faulty Clutch Pack Within The Transmission. The Mechanic Said That It Should Be Up And Running By Monday.

BernardL said...

Thanks for the update, Ramiro. I'm glad it will be on the road for you again soon.

Anonymous said...

Hey bernard thanks a million Your advice. got my truck up and running. I am gonna buy one of your books as a thank you! PEACE OUT! GRIMMETH

BernardL said...

I'm glad you got your vehicle going, Grimmeth. I hope you enjoy the book.

David said...

Hi BernardL,
Im looking at getting a 1999 Dodge Ram Magnum 318 v8. The owner says that the tranny is slipping and that he was told that the speed sensor is the problem. Now from Now from what you have explained above, replacing the correct sensor should stop it from slipping, yes? Is this an easy "do it yourself"? And if so, whats the average price for a sensor? Would it be as easy as checking into autozone and getting the correct one and replacing it?

BernardL said...

Forget the sensor, Dave. If the transmission slips, that's not a sensor fix. If you are really interested in the truck, gamble on a diagnostic for it at a real transmission shop so you'll know what you're getting yourself into, including them dropping the pan to check for debris.

MadWheeler said...

Just wanted to say thanks, BL. It is really decent of you to take the initiative to post such helpful data as this online for the DIY'ers to save time, money and frustration in times such as we live in. Kudoos to you! Thx again!

BernardL said...

You're welcome, Madwheeler. You're sure right about the times we're in.

LVNP said...

Hi Benard. I have a 2003 Dodge Ram 1500 4.7 V8- For a while now,on occasion, when my truck accelerates from first to second gear, the shift will thump into second (lurch if you will). A while back I did get a speed sensor code but it was not my rear diff that was bad. I had a service done at Dodge and the light was turned off but I still have this issue? Do you think the tranny is bad or can it be the sensor on the tranny? Thanks.Darryll

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