My neighbor has a 2020 Custom Trail Boss with 5.3 and 6-speed. He has less than 3,000 miles on the truck. It's his daily driver, and he tow a small toy hauler in the weekend to a place only 2 hours away. Engine already failed at 1,100 miles. Now his transmission is overheating. Loaded up, he not over the towing limits on his truck. Dealership said there's an issue with the trans valving. I'm not an expert on transmissions, and I have no idea if what the OP is experiencing could have anything to do with the trans valving, but thought I'd post up just in case there is a correlation. Sent from my SM-N960U using Tapatalk