The contact owns a 2023 GMC Sierra 1500. The contact stated while driving at an undisclosed speed, the Service Transmission Now warning light illuminated. Additionally, the contact stated that the warning light and a message indicated that the transmission would stop shifting soon. The vehicle was taken to the dealer; however, the vehicle was not inspected. The vehicle was not diagnosed or repaired by an independent mechanic or the dealer. The manufacturer was not made aware of the failure. The failure mileage was approximately 31,230.