I have an 05 Chevy Z71 extended cab, with a 3 inch lift and larger tires. I know, but it was 15 years ago and the dealer had installed the lift, 32 inch tires, and the truck was new. I really liked the look of it. It was geared 323 and would gear hunt all the time. I had 456 gears installed front and rear and it helped a lot, but truck is still pokey at best. The shift points are very low, accelerating from a start under part throttle and it is in 3rd gear before you can cross a four way intersection. Also it will not downshift into passing gear above 50 MPH. I have been told to disconnect the battery for a few minutes, then hook It back up and drive it hard. The computer will then set new shift points. Haven't tried it but might. Having said all that, truck has been pretty good, I had to replace the dash stepper motors, AC blend door, and heater relay. the truck has 88 thousand miles and people, mostly younger, want to know if it's for sale everywhere I go.