NHTSA Complaint #11656814 — 2023 GMC SIERRA 3500

The contact owns a 2023 GMC Sierra 3500. The contact stated that while hauling a trailer and driving approximately 40 MPH, the contact attempted to merge into traffic and the message "Restricted Power Mode" was displayed. During the failure the transmission failed to properly shift into a higher gear, and the vehicle failed to exceed 67 MPH. The contact stated that later while driving at an undisclosed speed, the check engine warning light illuminated. The vehicle was towed 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 33,800.