We had this happen on a Transam we put a 4L80E in.
It ended up being a valve in the valve body was sticking. Initail start we had all gears. Once transmission was warm, we would not be able to get it back into first gear. He had 2nd gear starts and everything else worked fine.
Took the valves out and used some scotchbrite pads on them to clean everything up and no more problems.
It ended up being a valve in the valve body was sticking. Initail start we had all gears. Once transmission was warm, we would not be able to get it back into first gear. He had 2nd gear starts and everything else worked fine.
Took the valves out and used some scotchbrite pads on them to clean everything up and no more problems.