Why wont it shift??!

.50 CAL · #1 Sun, August 14th, 2011, 06:19 AM

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??