The truck is a 1998 dodge 2500 4x4 cummins 24 valve.
The trans is shifting in an out of overdrive to drive in exess when cold in example 40 deg
weather. When warm no problems . Fluid and filter have been changed and still haven probs.I'm thinkin that it's the torque converter or shift silenoid
Any help would be appreciated guys. Parts and service I hope you'll have a idea for me.

 

When driving my truck on the freeway @ 65
@2000RPMs it will go up 200-300 rpms
don't know what the problem is would like
any help