Well i was driving my truck today and when i hit any where from 45-53 mph (not floored just cruising) my truck shifts down then shifts up very quickly. Its about to drive me nuts. it will do it almost everytime. I read some other post and heard of this APPS or something. Could that be it?

 

Try resetting the APPS. This has helped out some folks with a simular problem.

CLICK HERE

let us know if it helps.

 

This sounds classic. Electrical noise is the culprit.
Clean the battery posts, reset the APPS, and if it still does it, ( it will in time ), Get the filter. DTT makes a great on and not expensive. DTT

 

I was having the same problem, also in the 35 - 40 mph range. Resetting the APPS worked for mine.