I had a 2018 with 8 speed and was very unhappy with the transmission. It always worked, but was sometimes violent when shifting into gear from park. Even with letting the truck warm up. They did a fluid swap at 25,000 miles and it made it hunt around less resuming throttle from 5-10pmh turns when accelerating. I may have had a lemon, but my issues seem to have been common for 2018 8 speed (5.3 engine)