I'm sure it's as easy as a simple segment swap as there are Trailblazer SS's running 4L80's and I got my Trailblazer running a 6L80.

 

http://www.tbssowners.com/forums/sho...highlight=4l80

 

well from what i can tell it will work one way or the other 1. is doing a segment swap.
or just run it off the 4l60 program i all ready have in the car.
so i will be getting a 4l80e to go in it.
thanks for all the replies.
Donald