Ok, I've just about had it. My truck has not been able to stay in overdrive for months now. I have checked my old TPS, I installed a potentiometer, I bought a new TPS and nothing seems to help.

I just checked the two outside wires, and got 5.15v which is alright, if I'm not mistaken. When I check the signal voltage, it reads erratically from 4 millivolts to 7 mv. This is extremely low. Does that mean that my PCM is toast? Or should I clear my PCM and check again? This is driving me nuts! I can only drive 70km/h on the freeway (speed limit 100km/h) otherwise OD engages/disengages constantly

I have searched for low signal voltage, TPS etc and couldn't come up with anything. I have also followed the advice of www.dodgeram.org and it didn't change.

 

Try disconnecting alt field wire and then driving truck. RF noise is often picked up by the overdrive wire causing your problem. Did you try running a ground wire to pcm direct to battery ground? Also brake pedal switch can cause similar problem. Try holding up on brake pedal with foot to see if any improvement. There is also a flash that maybe needed to the JTEC controller.

 

Do i want to disconnect both field wires? What is a JTEC controller?

 

trans temp sensor can give you the same exact problem w no trans temp light on in dash. thats fixed/tested w 1000 ohm resistor and $.76 at Radio Shack

 

JTEC is mounted r/s engine firewall. It controls trans and charging system. Disconnect the field wires and tape them so they dont short on any thing. If trans works ok then you are getting alt noise causing problem.

 

As will a bad brake light switch.
Have you tried installing a lockup switch?
It will tell you if the problem is electrical or a mechanical problem in the tranny.

 

Thanks for the replies, guys! Sorry it's taken so long to get back to everyone, work has been ridiculous! So I have my 1k ohm resistor, will be fiddling around with that today.

The brake light switch is a little touchy, but not the problem. With my foot wedged underneath the brake pedal, lockup/OD still kicks in and out.

A lockup switch sounds a little bit out of my capabilities...if I can figure out how to hook up the resistor (and it doesn't work), I'll give it a shot.

Cheers!

 

Very, very easy.
Just follow these instructions> http://www.tstproducts.com/Torque%20...p%20Switch.pdf

 

The lock up switch is easy and well worth the trouble just as a diagnostic tool. Let alone for engine braking on the steep downhills in the rockies!

 

alright...another dumb question...the transmission temp sensor is located on the drivers side, about 18" back from the TC? Is it the sensor that is really easy to reach, located more on the bottom?

 

you have to trans cooler lines coming out of ur trans. a forward one and rear one. the front comes out and almost immediately curves under the bell housing. the trans temp sensor is right b4 the bend. points to the rear of the truck IIRC

 

Isn't 96 a re trans?

If so the temp sensor is inside the pan.

 

yes it is. i didnt catch that.

 

Okay, so I disconnected the two adjacent contacts (field wires I think) on the alternator, which cleaned up the function of the lock up clutch, but still didn't get me OD.

So, I called DTT to get a filter but they are out of stock for 2-3 weeks. Are there any ways to temporarily clean up the RF noise besides tinfoil? I will also be installing a PCM ground direct to battery as a safegaurd.

 

Well, I've installed the Noise Filter...didn't help. I wrapped the alt wires with tinfoil...didn't help. I exchanged my TPS for a new one. Didn't help. I installed a new PCM ground...didn't help. Checked the voltage at the APPS wire to the PCM, it's fine. Voltage at the TPS is low.

I'm still getting a TPS low voltage code with the OBD II. Would a direct ground at the TPS help this? Or should I bypass the existing TPS wire with a new one? I'm stumped...I took my truck in to the shop that rebuilt my tranny and he couldn't figure it out...I also had my heavy duty mechanic buddy (a 24v guy) spend a few hours on it, and he's stumped too...