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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. :)


441 comments:

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Bryan Watson said...

I have a 97 ram 1500 with a 318. Just pulled the old motor from the truck and replaced with a crate motor I bought. With the old motor, the grabs shifted fine with no issues, since new motor, trans won't shift out of first until you get up to 3000rpm and ease off the accelerator to get to shift, same for 3rd gear. Seems to shift fine when over 45 mph and with o/d turned on.

Bernard Lee DeLeo said...

Bryan. You'll have to at least have a computer scan done. I can't tell you anything from your description, other than something doesn't match between your engine replacement and the transmission. It has probably set a code.

Ken Clark said...

Hi I have a 2001 ram 2500 with a new transmission. The governor pressure shows 4.95v, 99% duty cycle and speed @ 107. On a friends truck it reads this if I disconnect the trans connector. I've checked all the circuits for a short but didn't find one. Can you tell me what I might be missing. I've checked the speed sensors & they seem to be ok. Thanks KRC

Bernard Lee DeLeo said...

Two things, Ken - you didn't mention having the computer scanned for codes, and you didn't mention doing the diagnostic check I have noted in the post:

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.

I can't tell you anything with the info you have. You also didn't mention doing a continuity check on the sensor wires from the computer through the connector.

justin berry said...

Hello
1999 ram 1500 5.2 automatic 4wd
I need an opinion,
During acceleration it stumbles almost like a misfire, shifting at high rpm, and motor has a strange deep Sound during decent acceleration. It has new plugs, wires, all new fluids and filters
Thanks: justin

Bernard Lee DeLeo said...

Justin. It could be a plugged catalytic converter. You'll have to have the back pressure checked.

Brandon Jerome said...

My 1998 Dodge Ram 1500 with 5.9 liter I replace the transmission about 6 months ago and just now starting to get a wine and it wont shift from first no code that I know of no speedometer issues just a loud wine wont shift from first I check the fluid noticed it was was low I put fluid in it and still did not fix my problem please help Brandon

Bernard Lee DeLeo said...

Brandon, you may have missed this note on the original post:

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.

You need to have a computer scan and these tests above run. I have no idea what's wrong with your trans from the info you gave me, other than if you ran it low on trans fluid for very long, you've probably cooked the transmission.

John Lovett said...

Hi Bernard, I have a 2007 Dodge Ram 1500 4.7 litter. When I start my truck up the RPMs will stay at 2000, after about 40 seconds it lowers to about 600 rpm. When I'm driving any speed over 30mph and either take my foot of the gas to coast or to break the RPMs will jump up to 3000 and I feel a hard jolt, sometimes its so hard the tires actually make a screeching sound. I have had about 2 or 3 occasions when I'm driving on the highway going anywhere from 45mph-70mph and all of a sudden the my truck losses all power and completely shits off. Any suggestions of what I might be dealing with.

Steve s said...

95 Dodge Stratus 47,000 miles, when I hit the brakes the transmission downshifted and would not shift out of 1st. after letting the car sit and get cold shifts fine after warming up the transmission down shifts and won't come out of 1st? no slipping. shift solenoid? any help would be greatly appreciated! !!

Bernard Lee DeLeo said...

I can't tell you, Steve, without scanner data, and you will need to have this test done at a shop if the scanner data doesn't reveal the problem.

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.

Unknown said...

hi bernanrd.. i have a 1998 dodge ram 2500 diesel.. it has the 12 valve mechanical engine and 47re auto trans.. when i come to a stop sometimes it does not want to move.. if i push the throttle too hard it will actually jerk into gear and stall engine... i did already have a full reman trans. put in.. fluid level is ok, replaced speed sensors, i get no fault codes truck sometimes does it once a week and other times once a month..if i put into nuetral and back into drive it does not work but if i put into reverse then back into drive it kicks right in and moves.. thanks.. john

Bernard Lee DeLeo said...

I'm sorry John, but it seems you still have internal transmission problems. I don't have any simple ideas for you to try other than to disconnect and clean all electrical connectors on the transmission, making sure the wiring's not frayed or broken, and free of corrosion. Make sure to clean them on the inside with WD40. A continuity check on each wire at the connector is something I always do, but you may not be comfortable doing. A reputable transmission shop would be your next step.

Juan Martinez said...

hi Benard. i have a 1987 dodge Dakota 3.9 what is normal for a ignition coil getting so hot you cant touch it . thank you for any tips on solving this j.r.m.

Matthew Cardin said...

My 01 cummins drives for the first 3 gears and then won't shift to 4th would you suggest speed sensor

Bernard Lee DeLeo said...

Juan, other than a bad coil or something crossed up in the ignition to the coil, I don't know. Coils do get hot, but excessive heat in any electronic part comes from resistance.

Matthew. I don't think so. You never mentioned having the vehicle diagnosed for computer codes and data, or how often you've serviced the trans. The diagnostic by a pro would be my first suggestion.

Juan Martinez said...

Hi Bernard does my 1987 dodge dakota v6 3.9 have any type of speed sensor ? thanks for any feed back.... J.R.M.

Debbie said...

Hi berard i have a 98 dodge durango 4x4 with the smaller v8 engine it read the codes p0500 speed sensor circut and the map sensor code,I changed both and the p0500 code is still there I reset the comp when this was done,meaning I took the neg cable off the bat and turned the key to start.Suv is still driving erratic and speed om is crazy or not working half the time please help.

Bernard Lee DeLeo said...

Juan, yes on the trans and on the differential.

Debbie - If you changed the speed sensor on the trans, you changed the wrong one. A PO500 is caused by either the speed sensor on the differential or wiring to and from it. Always use OEM sensors on Chrysler products too.

Dave said...

Hey Bernard this is Dave I've got a 99 4x4 318 dodge durango auto trans was running good the day before got in to go to the store the next day and it want shift ,reverse is good and 1st gear is good, will not go in 2nd,3rd or OD any suggestions would greatly be appreciated Thank You

Bernard Lee DeLeo said...

Sorry, Dave, but you haven't done even a basic code check for me to see. I would advise a professional diagnosis, including computer codes and this test you missed in the original post: 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.

96caravan sport said...

hi bernard, I have a 96 dodge caravan sport. its on 2nd transmission from dealer . replaced 10 years ago. it currently has 118k miles. upon starting , I put it in drive works normally and maybe after driving maybe 10 feet or it feels like maybe 5mph it goes into what feels like neutral but it is still drive. I stop it completely and none of the gears work. I restart it and it pop it back to drive and it works again but repeats the exact same thing so I do not get far. the codes my mechanic gave me are 36 - fault immediately after shift, 52- gear ratio in second, 74 - calculated oil temperature in use. I also called the molar tech support and they just told me it need a transmission replacement because the code , i forgot which one ,means internal transmission therefore must replace or rebuild. I am hoping to avoid that since although the 2nd transmission lasted 10 years it only probably had 50-60k miles on it.

Bernard Lee DeLeo said...

96 Caravan Sport - You'll have to get it professionally checked at a trans shop. They need to do the tests I mentioned in the comment above yours. Tech support is right about the code usually meaning replace or rebuild.

Gregory Capanda said...

Hey there! I have a 2002 durango 5.7 with a 518 trans. I have an intermittent problem with the trans associated with my speedometer. When the speedo stops working, the trans acts up. Or vise-versa. It seems to shift late causing the RPM to revv up before shifting hard into second gear. It doesn't always happen and when it does, I can't identify what it might be associated with. Any ideas?

Bernard Lee DeLeo said...

Gregory, the speed sensor in the differential sends the speed signal for your speedometer. You need to have it checked for code history before throwing parts at it though. In my experience, when the differential speed sensor goes bad, it sets a code.

Jonathan Bateman said...

I have a 99 Dodge cummins 24 valve that the speedo that sumtimes would work sometimes it wouldnt. I was driving the other day about 50 and it just all of a sudden went in neutral, now it wont go in any gear.

Bernard Lee DeLeo said...

Major failure would be my guess, Jonathan, but without any information codes or tests done as I described in the post I wrote, I have no way of diagnosing your vehicle. Take it to a professional trans shop would be my advice.

princeal said...

Hi Benard, i have a 2001 dodge ram 1500 5.2 v8 2wd 190,000 miles,
rebuilt transmission at 125,000, it has been slipping at starts, or give it gas and nothing then kick in. the other night going home on the hiway i see the rpms shoot up to 3500-4000 i take foot off gas pull over, get off exit so i can check it and revs but only get 25mph top speed, check fluid o.k., check codes get tps high voltage,
p01740. i checked pan and changed filter, same have 1st and rev, in limp mode, trans shop says 2400 to rebuild, any ideas. Money is tight, im taking bus and can only work half my shift.

Bernard Lee DeLeo said...

Princeal, I would agree with the shop. From what you describe, it would appear you need the transmission rebuilt again.

Shannon Sisco said...

Hi Bernard. I have a 1994 Dodge Ram 2500 5.9L Cummins, with a manual transmission. My speedometer works up to about 20-25 MPH, but cuts out and quits working at speeds above that. I have done some research and read that there is a Output speed sensor in the transmission that references speeds above 20 - 25 MPH in the automatic transmissions. Would the manual transmission have a similar sensor? I have already replaced the speed sensor on the transfer case thinking it was that. I have no other problems with the vehicle, and no codes are coming up on it.

Unknown said...

I have a 98 dodge durango and all of the sudden it has decided it does not want to upshift from first gear. I believe it is a 5.9 v8 4x4. I let it sit over night then reset the computer. That worked for a test drive then when I went to leave again it won't shift from first. Please help

Bernard Lee DeLeo said...

I can't help, Unknown. You haven't given me even a code your truck may have set. You need to have a computer diagnostic and a physical check as put in my original post.

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.

Unknown said...

Hello I have a 2000 dodge ram sport 1500 with a 5.9 magnum. Had a crsnk position sensor put in and no it feels like it's got a miss in it. Sometime if I'm cruzing say 35 mh. Or if I get into it. It doesn't happen every time. It ran good till the crank sensor was put in. Pls help

Bernard Lee DeLeo said...

Sorry, Unknown. I can't help you. You have no diagnostic information for me to even make a guess. I would suggest taking it in to a pro for diagnostics. The first step is finding out what is causing the miss, and what codes if any, are being set. I can't do that on the Internet.

lovelyviolet 73 said...

Hello Bernard,
I hope you can help me.
I have a 2wd 4.7v8 2005 dodge durango with a little over 130,000 miles.
Was driving when heard a loud whinny sound and dodge would not move in ANY gear as if in neutral, there were no warning lights (no check engine/ no check gages). Turns on and off fine just will not move. Checked codes and got a PO700 and PO888. Dropped the pan and nothing, just a little gunk on the magnet. We replaced the oil pressure sensor as well as the transmission oil and filter, but still nothing.

Bernard Lee DeLeo said...

Violet, with those two codes and the symptoms, my guess would be the transmission is bad. You'll need to take it to a trans shop for confirmation.

Unknown said...

I have a 2001 ram 1500 with a 5.9. When in park and neutral truck revs just fine but in gear wont rev above 2k. Any chance could be a sensor?

Unknown said...

Great reading material! In need of guidance, 2001 Dodge Durango 5.7 r/t. 46re. No codes, it has a sluggish acceleration. You can give it gas, it does accelerate but it seems as if I'm pulling something heavy (constant higher Rpms until I reach 15-20 mph). Also if I'm at a light (in drive, waiting) for an extended period of time I can feel a slight jerk, also when deaccelerating a slight bump going into 1st gear. Catalytic converter is fine, recently changed-spark plugs, map sensor, tps sensor, plemnum gasket, transmission fluid/filter. Thanks in advance!

Bernard Lee DeLeo said...

Sorry, Unknowns. I can't help you. You have no diagnostic information for me to even make a guess. I would suggest taking it in to a pro for diagnostics. The first step is finding out fuel pressure and having the transmission tested as mentioned in my post, and what codes if any, are being set. I can't do that on the Internet.

cathie casteel said...

I have a 1999 RAM 1500 with the 46RE trans.the other day drove approx. 30 miles.worked fine.shut the truck off for about 5 minutes then started driving and it wouldn't shift past second gear.transmission was not slipping at all and no check engine light on.checked fluid level and it was at the correct level.drove it home slowly and shut it off for about 20 minutes and drove it again and this time it shifted perfectly.drove it approx. 50 miles and worked fine the whole time.that night I changed the filter and filled the fluid to the appropriate level.and the next day drove the truck to work.i drove about 40 miles with no problem until I pulled up to the end of an exit ramp and stopped for about 30 seconds.I took off from the stop and the truck wouldn't upshift past second gear again. I pulled into a paring lot and stopped.put the truck in park,then moved the gear selector through all the gears while stopped and then ut it in drive again and drove another 3 miles to work with no problems at all.that evening I drove home and it still shifted perfectly.the check engine light never came on at any time and the transmission never slipped at all.could this be a faulty speed sensor or possible the governor/transducer going bad?

Bernard Lee DeLeo said...

Yes, Cathie. The test a transmission shop should do is the one I mentioned in the original post at the bottom. Here it is again:

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.

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