I need advice on a 4l80e. Some info about the car turbo sbc 4l80 trans with a TCI controller and 3.08 gears. It does not want to shift out of first gear when it is told to ( I have checked the controller ). It will shift 2-3 fine and 3-4 fine. If I am light on the gas it will shift. I have changed both speed sensors and the ttc because it didnt ohm out. Solenoids a and b both ohm out good. Thanks for any help and great site by the way

 

Solenoid feed hole in the seperator plate is too big.

 

Is this some thing that can just happen? I drove it home from the dyno 30 plus miles and all was fine later in the day I get in it to drive it to the cruise in and its doing this. Is this some thing in the valve body or deeper in the trans. Thanks help

 

did you check the wiring harness for the back VSS?

 

I did not but I am get mph reading on the dashboard and part throttle shift table. I wasnt getting one on part throttle but now I do after the new sensor.

 

Could the manifold pressure sensor cause this? If so is there a way to check it?

 

More info,
is it modded? VB kit?

Does it only do it at WOT or near WOT?

1-2 shift valve defaults to 2nd gear, so for it to not shift when the controller is commanding it you have:
1: Some idiot drilled the solenoid feed hole.
2: Solenoid is plugged up and not exhausting properly.
3: Excess pressure building up on the downshift side of the 1-2 shift valve, could be caused by VB mods or pump mods.
4: Weak or broken 1-2 shift valve spring.

 

It will shift at near wot
If i have it in 3rd when I pull out when it commands it to shift to 2nd if I shift the selector to 2nd it will shift
Dont know about the solenoid the trans has worked perfect for 6 years
I am going to check line pressure as soon as I find a guage