2018 Chevrolet Suburban engine problems

I purchased this vehicle in dec of 2019 used. 35,000 miles. Now has 88,000 and the transmission went out. Regular oil changes. No warning lights. No issues. Stopped running. After having someone look at it to see what the issue was, the mechanic said the entire transmission has to either be rebuilt or replaced.

The contact owns a 2018 Chevrolet Suburban. The contact stated that while driving at an undisclosed speed, the vehicle jerked with the check engine warning light illuminated and the vehicle inadvertently lost motive power. The vehicle was taken to the dealer; however, the vehicle was not diagnosed or repaired by an independent mechanic or dealer. The contact stated that he was informed by the dealer that the failure could not be duplicated, and that there would be a fee for a diagnostic test.