The contact owns a 2021 Chevrolet Tahoe. The contact stated that upon coming to a complete stop, the vehicle suddenly jolted forward independently. The vehicle returned to normal functionality, but the failure became a regular occurrence. No warning lights were illuminated. The vehicle was taken to the dealer, who diagnosed a failure with the valve body. The vehicle was not repaired due to part availability. The manufacturer was notified of the failure but provided no assistance. The failure mileage was 57,000.