cummins wont shift into overdrive
 

i bought the truck with a bad transmission. last week i had the transmission rebuilt and the overdrive does not work at all. the tc locks up perfectly but will not shift into overdrive. i had to install a tc lock up switch to make the tc lock but still will not shift into overdrive.... i have replaced the tps sensor and the crank position sensor and still have no progress. somebody help im stumped!

Have you checked the speed sensor

Overdrive
 

If it was the speed sensor that was bad wouldn't my speedometer not work?

Are you sure you gapped the crank position sensor correct?

Overdrive
 

Ya it was gapped correctly.

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i found an air bag sensor module under the seat that is not plugged into the truck... its black and has 3 bolt holes in it. would this cause the truck to not shift into overdrive by chance

Sounds like you are on it. Maybe a bad solenoid or leaky seals in 4 th gear. I now u didnt want to hear that. Autos are tricky just because it was rebuilt doesnt mean it was done correctly.:scare2:

Overdrive
 

Ya it was built correctly. Just bad wire somewhere. The truck shifts perfect now on a tc flip switch and an Od switch

The TC lock up switches work great! If your tranny isnt beefed up your gonna kill it though :argh:

Parsons im having the same problem with my tranny could you explain the od and tc toggle swotches so i can try that