gabbyfan

About 30,000 miles ago i replaced the original tps which had lasted 310,000 miles. Over the last month it has been a much bigger delay for the tc to lock up and for it to shift into overdrive like 52 mph and when i am going around 45 mph any slight acceleration will cause the tc to unlock. By the way it is a banks billet tc. Yesterday i had cummins set the overhead and change the fuel filter. When i got the truck back it was like a new tranny. It would shift into overdrive under any acceleration at like 35 and the tc would lock up at or under 45 even in hard acceleration and at like 27 mph when overdrive was off. I also could floor it when i was going like 45 and it would stay locked up. Then 2 hours later it went back to what it was before and even worse. It wont shift into overdrive til like 55 and any movement in the pedal around 45 will make it unlock. It seems like just about the only way to get it to shift into od and lock up is to back off on the throttle. Could this be a bad tps or a bad speed sensor? Any help would be greatly appreciated!!