lately my tranny has been acting like it is switching back and forth from T/H mode. it wont shift into 3rd until about 30 and OD until 40 at part throttle. but it seems like when the tranny warms up it goes away and shifts at the normal shift points. what does this mean? is it the ECM doing it or do i need a tranny rebuild?

 

Has it started happening since the weather has gotten colder? Older 4L80Es had this "problem" there was nothing wrong just the ECT got below a certain temperature it would go into a delayed shift mode. This would happen until the motor and tranny warmed up. If you want to come by my work I will hook up my Tech 2 and talk to the tranny guy. Send me a e-mail. It might be normal.

 

fast i sent you a PM