Trans won't downshift
 

At certain times the trans will stay in 3rd or 4th (overdrive) until I stop and turn off the motor to let it reset. When I start it up again I'm fine. This is a rebuilt trans (reputable shop) with a 3600 vigilante. It only happens once in a while.. Any ideas?

I'm going through a similiar problem. Be sure to read this whole thread here: https://ls1tech.com/forums/automatic-transmission/490146-weird-tranny-problem.html

Find someone with a tuning software (HP Tuners, Autotap, etc) and see what code(s) might be stored. Hope this helps..

Thank You...very Helpful Info.