IAt 70,000 miles, the trans in my 2017 ****HD went bad. and had to be completely rebuilt to the tune of $4000.00. The technician at the transmission shop told me that the 6 speed trans in these trucks were "dogs" .and some were going bad at 50,000 - 60,000 miles. A 50,000 truck that is supposed to be heavy duty should not blow a transmission, especially when it has been regularly serviced. User's recommendation: I hI have been buying Chevy since 1974. Maybe time to buy an import ??