I was driving up a hill passing a semi at 60 mph. The engine suddenly stopped running without warning. No warning lights, only a restart engine notice. The vehicle rapidly slowed and i was able to pull over to the shoulder without being hit by the semi. Unfortunately the vehicle came to rest at the crest of a large hill, at the end of a merge lane. It was a very dangerous place to stop. Onstar called the missouri highway patrol, the officer arrived and agreed it was in a very dangerous location and called a local towing company to remove the vehicle as quickly as possible. The vehicle could not be restarted or pushed as the transmission was also locked when we came to a stop. The vehicle was towed to the dealer and the next day i was told the engine had seized and would need to be replaced. The escallade only had 25,000 miles on the odometer and i had purchased it new 2021. The service manager stated the failed engine would be sent back to gm, but this was a common problem with that model engine (6. 2l) and that it may take a while to find a new replacement engine