OK, I am new to this forum, so here goes...
I have a 95 2500 HD ram diesel 4X4 with auto trany. 185,000 miles had a NEW trany put in about 30,000 miles ago.

symptoms:
when I am running down the road the trany seems to downshift a little 200-400 rpm. then back up to normal. I can duplicate the 1/2 shift by touching the brake petal as if to shut off the cruise. I have also had the overdrive unit turn it's self on while running about 60 MPH... all of a sudden it downshifts out of OD and the light is on??? I can turn the OD back on and it works OK again. with the little 1/2 shift it does not shift out of the gear it is in just a few hundred RPM's. As far as I can tell it does it in 3rd as well as OD. I am at a loss everything seems to point to the PCM but I am not sure and at $500.00 I want to explore all options.

The shifting up and down it really annoying any help would great

Thanks Craig

 

Sounds like it might be your Throttle Position Sensor (TPS) acting up. There's a procedure for checking it in the Tech Facts under 12 valve - Drivetrain. Welcome to the site, BTW.

 

When it "so calls half shifts" it is coming out of lock up. Check the tps for dirty/loose connections and adjustments. www.dodgeram.org look for tps Goodluck RIck

 

yep, it's the tps. i recommend that you first take the wires out of the wire loom---some have posted that taking the wires out of the loom stops it (it seems to be the last thing they do and it almost always works). you could take the tps out and clean it- that may help.

you're converter locks up in OD or in 3rd gear when overdrive is turned off. when you hit the brake, the converter automatically unlocks, hence why you can "control" the problem.

Tom

 

Good deal you guys are great, I will focus my attention on it. glad you thing it is not the PCM. one other note that might be relavent I got the truck from my father inlaw and he had a lot of mods done to it and one of those mods was a switch that would control the torque converter so you could manually lock the converter. I have since removed it. let me know what you think

 

Fill out your signature and tell us what all it has? It helps on questions you have and answers you get!!!, goodluck on the tps, Rick

 

good idea, done

 

Just curious,what did your father inlaw replace it with?? Sounds like you have been blessed as I am with a great father inlaw!! Keep us informed on the repair,Goodluck Rick

 

He was a good man, unfortunatlly he passed away

 

My truck was doing that and I took off the TPS and squirted WD40 around the part that moves, which cleaned it up, and that fixed it.

 

My condolences,cdarnell sorry to hear that.Sounds as tho you had a good one,so many do not,if you know what I mean,Goodluck Rick

 

you probably don't need a new tps. just rewire it. that will fix the problem. questions? let me know. scott hendren

 

Hey there Cdarnell
Sounds like the same problem as I had awhile back.For me
it was the throttle pressure sensor which is a little device
linking throttle to the tranny that works the lockout on the
torque converter. This is what they said they replaced for me
and I havnt had any trouble since.
Hope this helps.

 

like i said, don't replace the tps. that's a waste of $200.

just get a rewire kit and rewire the tps. it's noise in the harness.

good luck.
scott.
questions? email me.