Over drive not working right?
I have a 1993 2500 cummins,Need help on what I can do to fix an overdrive that shifts in and out of overdrive at about 65 miles anhour. The trans will shift into overdrive at 45,but when you get up to about 65 it will shift and run up to over 75 and then fall back to 65 and back up to 75 just back and forth. I herd that there war a shifting module that could be the problem.I'm looking for some help,I know it is not working right> Thanks for the help!!