Trans. kicking in and out of overdrive.......

[V6power87]

I am posting this for a friend,



He has a '92 D250 2WD, and when going down the road it will sometimes fall out of OD into drive. He checked the connections at the TPS etc. and all seems fine.



What do we look for next?

 

[sberrio]

Same thing happened on my 93. It was the TPS, even though the connections were fine. I was able to "FIX" it by spraying some WD-40 into the bottom of the TPS.

That's my only experience with that problem on a 1st Gen.

Good Luck,

simon

 

[paccool]

In Bushwakr's absence, here is his procedure for setting the TPS correctly. If this doesn't work, do a search for TPS in the first gen section, there is a whole list that comes up. Look about 10 from the top for one that has Bushwakr on the right hand column. It is titled "how to set up TPS"





Well, He**, that didn't work. I don't know how to copy and paste that file on this reply. Try the search, I was just looking at it.

Sorry.



He tells you how to set the thing up for the proper shift points.



Stan

 

[V6power87]

Thanks for the quick replies!!





How much is it for a new TPS sensor?

 

[paccool]

I have not bought one but went back in the archives and took a look. At the dealer, price is in the $225 range. From Cummins, Case500 said he paid 134. EOliver said he got one from Cummins for $51. As you can see, there is a big spread so I think you need to shop around a little - you can save some money!



Try unplugging and plugging back in several times. some of the guys have reported that took care of the problem. There is also a plug repair kit you can get if that is the problem. Like Simon said above, some of the guys have sprayed contact cleaner or WD-40 inside the sensor and that fixed the problem.



Lots of choices here so have fun! Let us know what you find.

 

[Evan A. Beck]

Its not always the TPS... Check out the tach signal too. If there is not a steady tach signal, it will go in & out of OD.

 

[Case500D]

Doh! They saw me coming

Hey Paccool,



It looks like the Cummins man saw me coming on the TPS Oh well, it kept the old gal on the road. Another thing, I think, it could be sparadically causing problems is the distance sensor, aka speed sensor. I know my truck is 4WD, but I would loose OD when it acted up. I also lost my speedometer too. Just a thought. Maybe there is a loose connection back there or something. Hope this doesn't confuse the heck out of anyone.



Jeremy

 

[AlK]

V6power87,

I believe this is the thread that paccool was referring to:



https://www.turbodieselregister.com/forums/showthread.php?s=&threadid=41200&highlight=Set+up+TPS

---

Al

 

[paccool]

Yep, thats the one! Thanks Al, one of these days I might figure this computer out.



Stan

 

[V6power87]

Wow... . lot's of good info here!! If I remember right I think he did say something about his speedo taking a dump for a few seconds also.



But yesterday I was riding along with him and it would just fall out of OD into drive but the speedo was ok.

 

[DPKetchum]

Hi,this trans downshift from 4th to 3rd etc. can also be a internal lip seal problem also. The speedo and trans at same time going up and down has been in these trucks for years. I had a 1990 gas that from day one did this and Dodge did 3,000 dollors in repairs over 4 years and once in a while it STILL did it. Now I've got a 1993 diesel that every now in then does it also. Speedo bounces and 3/4 in trans is errictic. ITS been a pain. I've tried the wd40,speed sensors,grounds etc. I TRY TO INGORE IT MAINLY FOR NOW>seems worse in rainy/humid weather but not always. I asked a Chrysler rep about this once,he said problem oh what problem!Then said 94 were out and that was their main concern. Oh well.

 

[TBrowne]

Had this problem last week. 92 W250, erratic speedo and would kick out of OD into third. Replaced VSS (vehicle speed sensor) and this fixed the problem

 

[RamAZ]

I had simular problems about 1 1/2 years ago on my 92. Took top off of TPS and sprayed contack cleaner in it and reset voltage to . 9 volts. Still shifted funny, hesitated into OD and such.



I looked at the speed sensor and found that the nut was broken, replaced with new one. I also replaced the trans temperature switch. The temperature sensor can make the transmission down shift for no reason, I think the temperature switch works both ways to cold no shift into OD and to hot shifts out of OD. The old transmission shifts great now, been that way for 18mths.



If you take a look at the speed sensor and the way it is designed it is bound to wear out. Remember to put dielectric grease in connectors, this will save problems in the future.



Jim

 

[boatpuller]

RamAZ,

Did you just pop out the funny shaped area on the top of the TPS or did you split it in half at what looks like a split around the center of the TPS, I have my old one and would like to get it cleaned up to use as a spare?



Case500,

the Cummins dealer saw me coming also, replaced mine a couple of years ago and it was around $140



Happy Rammin,

Caleb

 

[DPKetchum]

speedo boune and trans shift

The only other input I'll add to this is I hope some of your's stay repaired. As mentioned before I had a 1990 350 gas that did this and Chrysler spent about 3k on it over 4 years time. It was very intermittant,They replaced speedos,speed sensors,speed sensor wire harness,o/d switch,pcm,tps on throttle body. Some of these items replaced several times. IT alwalys malfunctioned again at some point and time and it may be a brief period(seconds)to on and off for several days and then go away. The 93 Diesel 4x4 I drive now more or less does same thing. It's been ok now for 2 months but on long trip pulling a trailer the speedo once in a while jumped from 30 to 60 and little jumps such as 5/10 mph variations in fast jerks and if you slowed down to engauge 3rd from o/d in would hesitate and do strange. Then all is ok for a long period. Seems worse towing or in damp weather . Called speedo exchage service one time to see if they had seen this problem and they said BOY HOWDY and said they did'nt want to try a repair on one of these again. Said they never fixed the ones they had been involved in said they believed a inherent problem. In fact I got a job at a Dodge dealer because this is how I met service manager dealing with first truck. It never got repaired.

 

[boatpuller]

Thanks for the info RamAZ