i have to say my GMC 5.3 8 speed feels better than my 19 RST 5.3 8spd......i dont know if its a fact, but it feels peppier with better shift points and more power.....i had a 2500 6.6l in between these trucks and am pretty sure GM didnt change anything but it certainly does feel like they refined it......GMC vs chevy idk, and its probably the exact same it just feels different......the whole truck just feels more refined than my 19....weather seals, tightness of door closing, noise, steering, motor, tranny, it just feels like different truck but the same all in one.....