Why wont it shift??!
 

Today my truck decided that it would let the RPM's get all the way to 3100 before it would shift from 3rd to 4th everytime. Also my overdrive OFF light is blinking and im throwing code P0781. What is going on? I tried reloading different codes but the problem is still there. People have suggested there is something wrong with the TC or the VB, Has anyone else had this problem??

Is your truck an 01?

Could be another mechanical diode failure or some type of internal transmission issue. Have you dropped the pan to inspect for glitter?

Yes I just changed tranny fluid and filer yesterday and the magnet had a lot of glitter and i found a long bolt/screw in the bottom and found where that went and torked it back in there, and yes its an 01.

Your answer is at Powerstroke Nation.

Mark Kovalski has answered your call.