I just purchased a 95 ram 2500hd v-10, 249,000 there are signs of wiring problems under the hood, getting under it and looking at the transmission the wiring hasn't been tampered with and made sure all was plugged in properly. about the 5th time, I drove the old girl the overdrive worked for 20 miles and then suddenly dropped down a gear as it had operated before. Testing the overdrive button it appeared to be faulty (no change of state between pins connections. plugged back in till I get a new one, next time I drove the truck the overdrive worked for awhile then kicked out. the indicator light comes on and off when using the O/D button, but no action in the transmission. I have checked the fluid level and cleaned the battery contacts prior to the functioning of the transmission. And began tracing the patch jobs on the wiring none associated with the transmission best to my knowledge so far. I'm wondering if I can apply 12volts and ground means to the o/d solenoid as a means of testing the function of the solenoid and transmission. also, better gas mileage till getting the circuit traced out. trying to locate a schematic of the wiring for the truck. help me daddy help me, please!

 

You can download the service manual for your truck from here. Wiring diagrams are in section 8W.

Trans gets power via the PCM controlled Trans Relay in the PDC. PCM controls the ground side of the circuit for O/D, and TCC. You can install a switch in the ground side of the circuit for both solenoids, to use for testing. (use the switch to provide an alternate ground path.) Are you getting any codes? Do you have a trans temp sensor on the cooler line going to the radiator? (it'll be back very near the trans.)

The O/D switch is just a momentary switch. It sends a signal to the PCM, and the PCM takes it from there. (turning on the light in the switch, and not grounding the O/D solenoid.)

 

I know this isn't related to the OP but where is the sensor if you have one?

 

Temp sensor? On the RH transmissions, it's in the cooler line, RIGHT near the trans. Lines comes out toward the front of the trans, drivers side. On the RE transmissions, it's part of the governor pressure sensor.

 

Ah that's right RE is inside of it. I still learn new things!

 

Yes it does have a temp sensor/ code 37/ and i thought 45 but isn't on the list i got. so have to recount the flashes.

 

If it actually has the sensor, and the sensor isn't working properly, or is reporting too high of a temp, the PCM will disable O/D, but, it should also turn on the Trans Temp lite in the cluster......

 

It has the temp sensor and that may explain the working for a bit then kicked out after the 15 miles of driving. No light on cluster though the dash trim was off also when purchased and may have a bad lamp. The patch wiring is tied into thermal overloads and battery ground. Is there an ohm spec on the temp sensor (no or nc) solenoid should be small and not to tranny case. I stopped on testing, replacing ball joints, brakes, tie rod ends, shocks, front wheel bearings and seals, rear shocks, and tranny fluid n filter. Will make wire repairs as I find them. The person who did the wire cobble knew only enough to be dangerous and the ol man I bought it from drove to the bar and home never fast enough for OD to engage. Replace the temp sensor is what you are suggesting? Correct

 

Temp sensor runs on a scale I do believe, it's not binary. Also, the PCM will kill O/D before the trans temp light actually comes on. You *should* see the 'trans temp" light in the dash when you first turn the key on, and the lights all test.

If you haven't already, get rid of the check valve in the cooler line going to the bottom fitting on the radiator. (it's right where the flex line hits the hard line, near the crossmember, right behind the radiator.) They are notorious for clogging up, and restricting flow.

 

thanks for the info last dodge pickup I drove was my DNR '80 150 w/4spd(granny low) slant 6 w/2bbl. Thanks again I'm a listening if you got more good info.