2023 GMC SIERRA 3500 Complaints

Transmission had a hard shift which jolted the truck switching gears to a lower one unexpectedly. It caused my body to jerk back. It happened 3 times. 2 were mild but the 3rd time was extreme. Always while accelerating. Average speed was about 50 mph when this occurred. Dealer has confirmed a failure of the transmission valve body. If the transmission were to be put in park while traveling, it could cause major accident and injuries. After the 3rd time the engine warning light came on and the truck went into limp mode.

We’ve had issues with the electrical system/brake lights when we hook any trailer (horse/boat/utility) to the truck. One issue is that the system shows unconnected and the trailer lights blink or do not work. We’ve brought this in to the dealer 3 times and they have yet to resolve the issue. The other issue of melted plastic on our rear sliding mirror. It just appeared one day, possible after using the rear defog button. We took it to the dealer and they also do not know what is the issue. We found several other blogs where owners have had the same issue. This is a newer vehicle, and we live in Southern California where the temperature is mild. It just appeared one day. We are concerned This is a safety issue with the electrical system melting the plastic and possibly causing a fire. Here is a link to a blog: [XXX] Lastly, this vehicle was advertised as having adaptive cruise and it does not have the capability (chip) to do so. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

The contact owns a 2023 GMC Sierra 3500. The contact received notification of NHTSA Campaign Number: 24V060000 (Latches/Locks/Linkages) however, the part to do the recall repair was not yet available. The vehicle was taken to the dealer however, a diagnostic test was not performed but the dealer provided a temporary repair by disconnecting the tailgate switch. The contact was advised by the dealer to access the tailgate to use the key fob or the button located within the vehicle. The vehicle was not repaired. The contact stated that the manufacturer had exceeded a reasonable amount of time for the recall repair. The manufacturer was made aware of the failure. VIN tool confirms parts not available.

I received a p0747 and p0700 transmission codes on my GMC sierra 3500. It would not engage above 3rd gear and I almost was rear ended by a Semi truck because I was unable to speed up. The vehicle CEL turned on and "Engine power reduced" notification appeared on my cluster. Engine RPMS were at 2800 rpm and my speed limit would not go past ~40mph. I currently have my vehicle being inspected by the local dealership. The vehicle currently has ~19,300 miles

CRITICAL PART FAILURE - The master cylinder attached to the brake pad is leaking at the seal where the piston is depressed into the cylinder. It's leaking brake fluid onto the driver brake assembly and some sort of cable. While this is repairable under warranty, this should NEVER ever happen on a vehicle. Arguably, the main part on the most critical system on the car - the brakes. Please investigate whether GM should be responsible for replacing this part on any affected vehicle for the life of the vehicle Thank you for all you do to keep us safe! Have a great day

Unknown Truck unexpectedly comes to almost complete stop between speeds of 35 to 55 mph. Occurs more frequently around 40 mph. Truck has been in repair shop and diagnostic can’t explain the problem.

On March 22, 2023, my wife and I purchased a new 2023 GMC Sierra 3500 Denali from Coast Buick GMC. Before purchasing, we asked the salesman if it had adaptive cruise control and lane keep assist, and he said yes and showed us the buttons and explained how they worked. We purchased the truck because it had these features. Four days later, on a trip out of town, we found that the adaptive cruise control and lane keep assist did not work. We looked online and saw similar GM vehicles with the same buttons, showing how to use the systems, but ours didn’t work. During our trip, the salesman texted me and said he needed me to sign a document. I told him that we couldn’t figure out the adaptive cruise control and lane keep assist, and Sal responded in writing via text, “OK be my pleasure to show you the adaptive cruise and lane keep assist.” We came into the dealership the next day, on March 28, 2023, with only 251 miles on the truck, and were told it didn’t have these features. The Dealership and GM have refused to make this right. GM’s design of the buttons in the truck for the warning systems closely, if not exactly, match the buttons for adaptive cruise control and lane keep assist options in other GM vehicles, which is very misleading. My brother-in-law has a 2020 model and he still thinks his has adaptive cruise control and lane keep assist, but they just don’t work very well, even after I told him it doesn’t. Today, while dropping off my truck at the GM Service Department for repair, the Service Department Representative said a lot of customers were told their GMC HD truck had lane keep assist and adaptive cruise control. This is a fraudulent or misleading design, which could result in serious injury or death.

I was in an accident and was hit in the right front side of my truck. The other vehicle was believed to be going around 50 mph and I had just rolled thru a stop sign. The other vehicle that hit me had the air bags deploy, but my airbags did not deploy. This is very concerning considering there was enough force to significantly bend the frame on my truck. I was transported to the ER and suffered internal organ bruising due to the accident. If the airbags would have deployed, my body could.have not jolted so much causing these injuries.