94 cummins shifts fine but no overdrive
 

I have a 94 cummins with 159,000 on it and just last night the tranny stopped going into overdrive. So I change the TPS with one I had that was new on my 96 cummins. That didn't help at all. It was low on fluid so I topped it off that didn't help Esther. So I'm lost I don't know what could be wrong with it:argh:.And I don't know what to check for under there. So some feedback would be great.

Is the TPS adjusted and the tv cable? It could also be your OD and lockup soleinoids, and even your throttle linkage if it aint adjusted right. Haha just noticed your from Rhode island I bought my truck down there a few years ago, got some family there to. Diesel prices suck there lol

I this a 47RE or 47RH cause the RH is hydraulic and the RE is electronic so I believe its different if its a RH, im not sure if it has a OD and lock up solenoid, but you can atleast check the tps and tv cable.

What's thetv cables? And it acts like the transmission is in the overdrive off position like when you push the button on the dash. And yea theydo suck here lol no one around here has a lot of diesels rather haha

The TV cable is used to control the tranny pressure and shift points based on the throttle I believe, easiest way to find out how to adjust it and find it is use the search on here or just try google. Ive never messed with mine yet so I cant really help ya there, I need to check mine aswell cause mine dont shift right since I got it.

Also do you know if I could cut out a piece of the steel tranny line and replace it with rubber hose?

Does your converter lock up?

The convertors locks but only with the overdrive off button. If u take that off and you go down the highway it should hit it about 50 to 55 mph. But it dosnt do that:argh:

More than likely the TPS but it could be the OD solenoid. Just had trans rebuilt on mine. When OD clutches went out the converter would still lock, The ecm didn't know the OD was not working, so I would think it is something else other than the clutches. I wired into the OD plug on the trans and put a switch to ground to see if I could manually engage OD and it would not. After rebuild it would. Think you can do it up on the ecm plug but not sure what #pin to tie into. The lockup is pin 54 and I think pin 55 is OD but not sure. Someone else might know for sure. If you wire a manual switch it will let you konw if it is the solenoid or something else.

do you have a lock-up switch? if not jerry rig one take it for a test drive and flip the lock-up switch. see if that locks you in.

Does anyone have the directions to put the lockup switch on? And will it hurt my transmission?