NHTSA Complaint #11684267 — 2024 GMC SIERRA 2500

Problem #1: Trailer brakes failed while pulling 40' fifth wheel trailer. Was driving at about 50MPH on a 55MPH road and was approaching a stop light. I went to apply my truck and trailer brakes simultaneously and quickly found out I had "lost" my trailer brake. This happened another two times within the next 10 mile trip to my house. I immediately disconnected my trailer and took my truck to the shop. The GMC Dealer fixed this issue, however, it is both scary and extremely dangerous to the public when something like this happens on a brand new truck. Problem #2: Right around 30,000 miles I was driving (unloaded) down the road at about 35MPH when I felt a hard clunk in the transmission followed by grinding noises - immediately a notice flashed on the dash stating the truck went into reduced acceleration and the check engine light came on. I brought my truck to a local GMC Dealer to be serviced on June 19th and they advised me it was the Allison transmission valve body. The part has been on back-order and my truck is still at the dealership sitting in the back lot with at least 4 other 2024 HD models. I called GM twice to inquire about Safety Recall N242454440 (covering 2020-2022 GM Vehicles) and recommend that it get extended beyond 2022 since the problem with the transmission valve body has not been resolved yet. I have not heard anything back from them since that call back in June.