I have a 2003 RAM p/u Cummins with the Automatic Trans. Occasionally it won't upshift out of low. Did trans service at 60k miles. Now 85k miles. No severe use, ex heavy towing. Doesn't do it all the time. Can go for days,weeks no problems, then all of a sudden it won't upshift. If I pull over, shut down, restart, it often clears up and runs/shifts fine. I have no clue what the issue might be, electronic control, internal to trans? Any ideas out there. I am totally stumped. Love the truck but getting a bad attitude about this intermittent shifting problem.
Thanks, Steve M Romney, WV
stevenmartin@frontiernet.net

 

You might need to have the Transmission reprogrammed. Is your tranny rebuilt. I have an 03 also but had to have it rebuilt. Taking it back to get some adjustment done to it. The computer is stacking shifts and when I stomp on it, it will red line and wont shift untill I let off the pedal. Try reprogramming it and see if that helps. Thatsthe only thing I can think of. good luck

 

What gears is it having a problem shifting to/from. Your tranny my need a band adjustment....something the owners manual reccomends every 30k. Or you could have a bad ground connection somewhere. Check the grounds on the batteries, engine, tranny, frame to body, any others you can find. Give us a little more info as far as what gears are giving you the problem. If you don't know what gears are giving you the problem, tell us what speed you are having the problem at.

re-read your post.... When you say it doesn't shif out of low, do you mean from 1st to 2nd?
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