Hey new to the group, got an issue with my 6L80, it's been rebuilt drove fine for a while now it's popping up with code P0700 and locks me into second gear. Any ever dealt with this before or got any ideas what it could be? Thanks in advance.

 

p0700 is a generic code. You'll need a professional diagnostic tool to scan the TCM to see what's wrong. Rebuilds rarely last very long though.

 

when I got it scanned with a snap on scanner I believe these were the two codes that popped up
P0872-00

P0989-00

 

seems that it's having pressure issues.
How many miles on the thing? Is the fluid full? What is the condition of the fluid? Have you been servicing the transmission regularly every 50k or less when towing?