4l60e tuning
i have a silvarado 2010 4.8 4l60e it shifts all 4 gears just around 50mph after swapping the tcm and then its gets stuck on 4th with high rpm and speed so no slipping but when i speed up like 120 the rpm will be like 5000 on 4th .
i wantrd to know if i have a tuning problem or mechanical i just rebuild the tranny coz of the same problem and no luck .
here is a cooy of my tune file

