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?

You probably should check the voltage on the TPS to make sure it is correct. Here is a link on how to clean and set voltage on used TPS. AS for the lockup switch just do a search on mystery switch or lockup switch.

Dodge diesel maintenance tips

How do u hook up the wire without cutting the orange and black wire it's confusing

you just tie into it and the switch grounds the circuit out. and yes it will hurt your tranny unless you use it just right. i recomend using it as a dignosis tool then forgetting you ever had one.

Yea that's what I'm gonna do lol. So I have to cut that wire in order to hook up the switch right? And also will low tranny fluid make it not shift into overdrive? Cuz I had a tranny line clip fall off and the line blew off today lost alot of fluid but the tranny still shift fine I don't get it. I use the button on the dash and it shifts into overdrive. So it seems like that overdrive off button has an electrical problem? But idk anything about electrical so I'm screwed:scare2:

Do not cut the wire, just trim the vinel cover back and tie onto the exposed wire, run the wire you just hooked up into the cab, get a switch and hook the wire to it and the other side of switch run the wire to a ground. once it is in 3rd gear ingage switch and lockup should happen. Be sure to turn off before you stop or it will kill the engine. This will not ingage the OD and that is what you said your are having trouble with.

I really think your TPS just needs adjusting. Mine would go in and out of OD, I check the voltage it was .69 volts at idel, I set it to 1 volt. It would not shift at all so I took it off and cleaned it reset to .95 volts and it has worked great sense.

Ok cool. I'm just gonna try it and se if it works. I changed the TPS but everyone says to check the volts Idk how to that lol. And on the dodge maintnece tips it tells u to rotate it to get more volts. So do I just take the TPS and turn it up more so the plug isn't at the angle and it more straighter than rather pointing down?

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I was just lookin at the tranny on the truck and it looks like the tv cable spring is pretty shot. Will that have anything to do with it?

that will fry your tranny. at WOT the TV lever should move full travel.

What will fry the tranny moving the TPS? And I can move the tv cable by hand should I be able to do this:scare2:

if the TV cable and lever is messed up. no the TPS can be moved fine. but your tranny needs to be able to make enough throttle valve pressure to overcome things in your tranny if this is way out of wack awful things may accure.

Oh I c. So should I put a new spring on it and try that out? And I rotated my TPS today and still nothin I'm lost lol. Gonna try to Jerry rig that switch tomorrow just to try it

I tried the switch and it works. I also changed the tv cable from my 96 and it didn't make a difference. It actually made it worse. It made the pedal get real hard and made the truck idle higher. The one that I took off completely broke it was so rotted. Does anyone know where I could purchase a new tv cable.

I tried everything as listed above,, had enuff and took to transmission shop , OD clutched were shot $500 and good to go