Sounds like it is shifting at to high of a mph and hitting the rev limiter. Try dropping the mph back down some or raising the rev limiter. It will get worse with the turbo because it will go through the rpms much faster. A built tranny will be in order pretty quick also. A 4l80e will be much more involved since it is awd.

 

Yeah, im not sure how or if you can adapt a 4wd 4l80 to the AWD ss setup or not...I think my friend still has his 03 copy of HP tuners so i will give that a try.

 

ill try to borrow a friends hp tuners this weekend and play with it a little.