2001 Dodge 2500 4x4, 24 valve Cummins.

When my truck tries to shift from 3r to overdrive at about 45-50 mph it doesn't seem to complete the transition. It revs up and down like it doesn't know where to shift to. Also if you are trying to go into passing mode at these speeds it will cannot make the connection. The transmission seems to be strong after if decides what gear to be in. I have began just driving with overdrive off at slow speeds.
Any suggestions ?

 

Check and clean all your grounds...

Check for codes.

 

You are describing what happens when the converter tries to lock but the signal from the computer cycles back and forth.
It is electrical noise going INTO the computer.
Grounds corroded, weak batteries, alternator issues are several causes.
Sometimes you can fix it by wrapping the big wire from the alternator to the passenger battery area with aluminum foil!!!

 

I will give the foil a try. Thanks !
I'm not a mechanic by any means. By corroded grounds do you guys mean the batteries ?

 

Check every ground on your truck and sand them down. I went through this for 2 years, and the cause was one of my batteries was a little lower than the other. Replaced both batteries and hasn't hicupped since.

 

Thanks I will have them checked

 

Vman, here is the normal plan for what I dealt with all spring/summer and you are now dealing with. There are a hundred opinions about what works best so I will go from cheap/easy to harder.

1 - clean all grounds off negative terminals of batteries and coat connections with dielectric grease.
2 - add transmission noise isolator from Geno's Garage(I got lucky and have been able to stop at this step)
3 - cut and re-route wire from PCM to APPS. Let me know if you need more info on this one

I would recommend cheap and easy steps first.

 

I took the recommendations about cleaning the grounds and it worked !!
Thank you all for your reponses you have saved me a lot of time, energy and money. You guys really know your stuff. Thanks to the forum also.