The contact owns a 2021 GMC Sierra 1500. The contact stated that while driving 30 MPH, there was an abnormal knocking sound coming from the engine compartment, after which the vehicle lost motive power. The contact was able to pull over to the side of the road. No warning lights were illuminated. The vehicle was taken to a dealer, who determined that the engine needed to be replaced. The vehicle was repaired. The contact stated that prior to the engine failure, the transmission was replaced. The manufacturer was not notified of the failure. The failure mileage was approximately 20,000.