1992 ram 350 diesel tranny problem

my 1992 ram 350 w/cummins diesel has started to slip in and out of overdrive. it is smooth up to then and seems to be worse after warmed up. any ideas?

Did you check the fluid first?That is the first thing to check,if the fluid looks black and smells,the transmision needs rebuilt and it is an easy transmission to rebuild with a new torque converter.Do not use the old torque converter over,you do not want to do the job twice and do it once.

The fluid is clean. A buddy said it might be a speed sensor. Any thoughts?
Thank you for your reply...

Jim

I would check the tps [throttle position sensor] first. You will find it on top of the injection pump. There is a shaft below it that goes into the pump and a hex nut on the shaft. There is a plug with three wires going to it. Take a volt ohm meter and press a paper clip into where the center wire goes into the fitting. Conect the plus probe of the meter to it and ground the minus probe. Turn the key on without starting the truck and the reading on the meter should be around .08 volts. Now take and manualy open the throttle slowly till its wide open and see if the voltage rises evenly with no jerks or the like. With wide open throttle the voltage should be around 2.8 or 3volts . Mark down the voltage on a piece of paper for starting reference. If it is out too much you can adjust it by using a wrench and turning the tps shaft one way or the other VERY SLIGHTLY. It does not take much to change the voltage. Its the tps switch that controls your overdrive in and out. If the voltage is not smooth when you open the throttle Im not sure if it can be taken off and cleaned or not. I had the same problem with my old 92 ctd and after adjusting the tps it has shifted like it should ever since. Hope this helps...good luck......Regards...truckin @ smilin

Did you check the fluid first?That is the first thing to check,if the fluid looks black and smells,the transmision needs rebuilt and it is an easy transmission to rebuild with a new torque converter.Do not use the old torque converter over,you do not want to do the job twice and do it once.


why would you not want to use the old torque converter?
im curious because ihave this problem

Bratt, when the tranny is out for a rebuild it is best to change the torque convertor because the origional one is very inificient/loose and dosent get the power to the ground like it should. A new tq with around 89 percent would make a world of difference to the way it drives and shifts. Also a lower stall to take advantage of where the torque of the Cummins engine comes in at around 1600 rpm. While spending the money for that a good valve body set up and it would not feel like the same truck....

I have a 92 with 318. It would not shift into overdrive. Took it to one place and they said replace it, went to another place, he dropped the pan, said everything looked great, flushed it with a cleaner, put new fluid in and some Lucas treatment and it shifts like new. He told me alot of people just replace them when it is not really needed. Not sure if it is the same tranny as yours but thought you might like to hear this info. It was less than a 200 dollar fix.