My 2025 Certified Pre-owned, 10 day old truck with approx. 6200 miles, was parked and I was unable to shift into reverse (as if in neutral). I put the truck in drive and entered the highway. About half a mile later, multiple warning lights appeared and the truck slowed, unable to shift out of gear. Luckily, there was a dealership a few miles away so I drove the truck there slowly and on the shoulder as much as possible. Upon inspection at the dealership, they told me that the valve body needed to be replaced. After the repair, which only took a few days, the dealership was test-driving the truck when the powertrain completely seized. They attempted to restart the truck but burned out the starter and fuse block which was also replaced. After a GM engineer gave the mechanics permission, they dropped the transmission to find that it was completely seized and had also seized the engine, though the engine was reportedly not damaged. The entire transmission was replaced and the truck was returned to me with about a month of downtime. This was a clear safety issue as the truck stopped working while on a highway. Luckily, I was in a heavily populated area where help was available. The transmission was returned to GM for further inspection and the repair was fully covered under warranty. Prior to the incident, there were no warning lights/messages, but only appeared after the issue.