transmission no overdrive

I have a 2001 3500 dodge ram cummins diesel that won't shift overdrive Dealer tested it ans said trans needed rebuilding so We installed another trans and it does exactly the same thing no 4th shift if you hit the overdrive lockout the light comes on but thats all. Top speed is 72MPH at 3300rpm. Which is normall for no overdrive. Is there a way I can bypass the ecm to manually shift the trans? I think I may have a broken wire in the harness to the trans. Does anyone know what color wire should be hot to engage the overdrive? Truck was wrecked and we lightly streched the trans harness as we removed the cab from the frame. I feel that is where the problem is but don't know which wire to test.

If you didn't have overdrive prior to putting in a new transmission, chances are you have a problem in the PCM which controls how the transmission shifts. I suggest letting a transmission expert look at that. As far as the harness being stretched, that's another possibility. Does you check engine light come on?

I have a 2001 3500 dodge ram cummins diesel that won't shift overdrive Dealer tested it ans said trans needed rebuilding so We installed another trans and it does exactly the same thing no 4th shift if you hit the overdrive lockout the light comes on but thats all. Top speed is 72MPH at 3300rpm. Which is normall for no overdrive. Is there a way I can bypass the ecm to manually shift the trans? I think I may have a broken wire in the harness to the trans. Does anyone know what color wire should be hot to engage the overdrive? Truck was wrecked and we lightly streched the trans harness as we removed the cab from the frame. I feel that is where the problem is but don't know which wire to test.
No codes but Brake light and anti lock light comes on and off intermitaly When I clear the pcm it will shift overdrive. Then goes back to not shifting

No codes but Brake light and anti lock light comes on and off intermitaly When I clear the pcm it will shift overdrive. Then goes back to not shifting

I have a '94, 5.2L, 2WD that does the exact same thing. I just had the fluid and filter changed, disconnected the battery to clear the codes, and it didn't help. Went into OD once or twice, then made some funky noises and went into limp mode again. Mine also does something else kind of strange. When I come to a stop, if I hit the gas immediately after stopping, it feels like the transmission slips until it revs fairly high, then it engages all at once really HARD. Soooooo, from what I've searched out in the rest of the threads on here, I think I'm going to change the Shift Solenoid, Governor Pressure Sensor, Speed sensor in the rear pumpkin, and get rid of that plastic check ball in the fluid cooling line. Hopefully that will get whatever problems I'm having solved. Is there anything else I should be looking at changing? Valve body maybe?

Time to get it on a good eng/trans/ABS capable scanner and check it out.
On abs brake stuff when the light comes on get a scanner on it before you shut the engine off.
The scanner should show some problem history or present.
Get codes and post back codes.
It looks like the dealer should have tested it out before getting rebuild happie like some of the trans shops.
MT