HI evryone i have a strange problem maybe some of you f body experts can help. I have a 95 z28 with a 4l60e. The tranny is a brand new unit from a reputable builder and it seems to not shift from 2 to 3 or from 3 to 4 and not even overdrive. The strange thing is that when i unplug the harness from the tranny it doesnt even throw any codes and there is no ses light. This is the second tranny and its the same thing. my stock unit would shift good until it was under throtle then it would just hit the rev limiter and not shift. I even had the pcm tunned by pcm4less and its the same thing nothing different. I would also like to Know how to tell if the car is obd1 or obd2. The car is oringally from californa. thankyou

 

Hi the first thing is there is definatley some issue with the PCM if you can unplug the harness and set no codes or SES light.It should set a circuit fault code for every solenoid in the trans when unplugged. Do you have and old PCM laying around you can try. The odds of two trans doing the exact same thing is very unlikley. Also check all your fuses, Under hood and dash. A 95 is OBD1. I was thinking this though what if the PCM was flashed for a manual trans if thats possible I am no tuner ?It definatly sounds like a very unusual problem though. Let me know if I can be of any technical assistance. There are many test that can be performed.

 

Does any body else have any thoughts on this

 

Were you able to secure a different PCM to try as I suggested ?

 

Yes i did and it is the same thing.