I have a 2000 TA and i did a t56 to 4l80 swap with a yank converter. when on the hiway approaching 70mph my tranny unlocks and then acts like its in neutral and searching for a gear. this happens at the 2500-2800 rpm mark. im using both vss sensors with efi live cos5.

car has:
yank ss 3600
410
cammed ls1

being the second tranny and still having issues in curious as to if its in the tune and what perimeters i need to look at and maybe a sensor as well. the car shifts through all the gears and locks up as well. this is the only issue i get but i dont get any codes.

any help would be appreicatied!!

 

Sounds like its returning to 2nd or 1st. Are you sure you are running a 4L80 segment?
Command each gear as you accelerate and see if it works.

 

Ill give that a shot. I just gotta get time to get it to my tuner. I hope this is something simple.

 

well we discovered the seg swap corrupted upon install and thats what did the first tranny in(plus it had a million miles). Got a good solid tune and a fresh tranny in it and its amazing. gotta get a few things with the shift points fine tuned and this thing should be good to go!!!

 

A ha....mine's doing something similar to that. Sometimes too, it seems when I shift it out of park it has no gears. Put it back in park (sometimes it takes a couple of times), and then shift down and it has gears all of a sudden. Strange. We just put this thing in, still working out the bugs on it

 

I grabbed the 60e-80e harness which requires no segment. Controls the 80e with the 60e segment. Plugs and plays.