Hi all! I too have a 2020 TB w/the 10 spd & 5.3. At 3800 miles I left the house & the truck made a hard, truck jolting bang into the next gear. Stopped to pick up some dinner & NO reverse! Good thing I could drive straight outta there. Checked this site & saw the low battery issue might be the culprit for trans, so I charged it overnight. Next day same issue, hard banging shift, idiot lights on dash, stuck in gear. Take off from a stop sign was like riding the clutch in a stick car. I had to shut it off, restart it, take off, bang, drive to dealer. They ordered a new valve body & it's been ok since. I don't drive it much. lost faith in the truck, gm wont buy it back. I've been buying GM trucks for the past 12 years, this is # 7. Very disappointed & don't know what I'll buy next.