I just rebuilt my 4L80E in my 02 Silverado 2500HD.. Put new TC in, (DAACO), new pump gears, etc.... Started it, shifts firm onto reverse, but seems to have only 2nd gear forward gear. This sounds like it is in limp mode. I did not change/replace the shift solenoids. I do not have access to a code reader and need this back on the road ASAP. I am thinking of dropping the valve body and checking all the valves and springs to ensure no one are stuck; all check ***** were replaced in the correct locations..... Any help will be greatly appreciated.

 

Join the club. Misery loves company.Rebuilt mine and I have the same symptoms as you.

 

So you never figured anything out?

 

Not yet, I pulled it and tore it Back down. Im gonna try some new electronics and do away with transgo's seporator plate.Was this your first build?

 

0n a 80e, yes. I was pulling a trailer home when it blew a seal (forget which piston), went into limp mode. Tranny was toast, weak when I bought it so I went ahead and rebuilt it. The front servo pin was broken, front planet had to be replaced, all new steels, etc.. I'm getting ready to go and warm the garage up and check the main wiring harness to ensure it is connected right. Had a friend helping me and he may not have connected it all the way.. It has to be electrical is what I am thinking; I tore it apart three times to figure out where the center support spacer went (yeah, I know) so the guts are solid and correct. If I cant correct it electrically I will drop the valve body next.

 

What is the method for the tune? Segment swap or relay? When I first did mine I copied all the tables over and had similar symptoms. I later realized you need to do a segment swap as there are hidden tables that get swapped over. Just something to think about.

 

Join the broken 80e club