The contact owns a 2021 Chevrolet Silverado 1500. The contact stated that during cold starts, the transmission was slipping, jerking, and banging. The failure eventually worsened and began to occur after the vehicle was driven and was warmed up. Additionally, while decelerating, the vehicle erroneously lurched forward. The vehicle was taken to the local dealer who diagnosed that the transmission valve body was faulty and needed to be replaced. The vehicle was not yet repaired. The manufacturer was notified of the failure. The failure mileage was 6,000.