2025 GMC Sierra 1500 transmission problems

Filed Nov 2, 2026 · Electrical, Engine · NY

Vehicle is a 2025 Sierra 1500 Elevation and has made a rattling noise since purchase in May 2025. Radio had electrical issues and required full replacement. Two weeks ago, while driving home on the thruway, the vehicle began to shake violently and display critical warning errors on the infotainment system, locking up and slowing down. Once I pulled over and turned the vehicle off, it would not turn back on. Towed to dealership, where I was told it was a sensor issue that could be fixed the same day. A week later, I was told there was a bent valve that required repair. It has now been two full weeks with no updates on what's wrong with the vehicle or how long it will be under repair, but based on similar complaints, it appears that it will need a new engine since this is a known recurring issue with this model vehicle. This was a massive safety risk to myself and my children if I had not been able to slow down and maneuver the vehicle off the road when it died.

Filed Oct 31, 2026 · Transmission · OH · fire

On XXX, my 2025 GMC Sierra 1500 AT4X AEV experienced a catastrophic failure while driving on [XXX] Oh. I had approximately 75000 miles on the vehicle when this occurred. A load explosion from underneath the vehicle and smoke, accompanied with metal thrashing noise and loss of power while in the far right hand lane of the highway. Coming to a stop, I saw fire in the grass shoulder so I inched the vehicle forward away from the fire by a couple hundred or so feet. A passing motorist called the fire department and police who extinguished the fire. I had the truck towed to Knapps Motors Chevy in [XXX]. After looking at the truck, they determined the transfer case siezed and luckily exploded the housing rather than locking up the wheels. If a motorist would have been to my right, they would have been the victim of metal shards and burning oil. This not to diminish the terrible possibility of the wheels locking while driving at 75 miles per hour. After working through GMs customer service line, they have been of no assistance whatsoever. They are pushing the repair on the extended warranty company Portfolio, who is in the process of fixing. I've been without a vehicle for more than a month, as im told the transfer case is a known issue and has an updated part number. The 2026 model year has a federal do not drive recall #26V289 due to an improperly built transfer case missing an oil pickup tube. This has been a terribly unnerving experience and feel this truck should be also involved in the recall. Please contact me at [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Oct 21, 2026 · Electrical, Engine · TN

The engine locked up and stalled out while driving. GM replaced engine but still experiencing issues. Dealer has admitted that they will likely recall my model year since it is an ongoing and same issues as recalled trucks. I have a vehicle I am not confident in nor safe it since it stalled while driving.

Filed Oct 20, 2026 · Engine, Fuel system · TX

Engine lost power and is smoking profusely. An independent service center told us there is a problem with one or more of the cylinders. No, there were no warning lamps. It's here, but we can't drive it.

Filed Oct 6, 2026 · Driver assistance, Transmission · OH · fire

I was driving at 70 mph on the highway. I heard clunk and then rattling and saw smoke while losing power. Check 4wd warning illuminated. Came to stop in busy traffic and where I first parked on shoulder, saw shoulder of roadway smoking and on fire. I pulled forward 100 or so feet slowly while hearing more grinding rattling cranking. Came to stop. Fire dept arrived and extinguished roadside blaze. Called towtruck and had towed to [XXX] in [XXX]. 75k miles. No warning just catastrophic failure. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Sep 17, 2026 · Electrical, Engine · 34,637 miles · MO

The contact owns a 2025 GMC Sierra 1500. The contact stated that while driving approximately 5 - 10 MPH, the vehicle went into LIMP Mode and failed to properly accelerate, and the transmission unexpectedly downshifted. There was an electrical malfunction, which caused the transmission to downshift. An unknown message was displayed on the instrument panel. The contact stated that the network was not operating at the correct voltage due to the wiring harness. The engine light illuminated after the failure. The vehicle was towed on two occasions to the dealer to attempt to duplicate the failure. The dealer was unable to determine how to repair the vehicle. The vehicle was driven to the dealer in LIMP Mode. The manufacturer, General Motors, was contacted by the dealer, and the contact also reported the failure to the manufacturer. A General Motors service engineer had inspected the vehicle. The failure mileage was approximately 34,637.

Filed Aug 29, 2026 · Engine, Transmission · TX

Engine started knocking at 18k miles and took to dealer and they found metal in the filter and installed a new engine and also replaced the midplate gasket on the valvebody due to a harsh downshift without codes in the system this engine is going on 2k miles and it seems to be fine now but the problem with 6.2 was only supposed to be on the 21-24 models and mine is a 25 model and already had a replaced and nothing from gm was said to extend the warranty on this model and powertrain

Filed Aug 28, 2026 · Acceleration, Engine · LA

I own a 2025 GMC Sierra 1500 Denali equipped with the 6.2L V8 L87 engine, VIN [XXX]. The vehicle had approximately 35,000 miles when the engine experienced a catastrophic engine failure. Prior to/during the failure, the vehicle experienced abnormal engine noise and a loss of power. Multiple warning/alarm lights appeared on the dashboard, including the Check Engine and Traction Control warning lights. The engine failure resulted in a loss of motive power and made the vehicle unsafe to operate. PHONE# [XXX] The sudden loss of engine power while driving created a serious safety hazard because the vehicle could no longer operate normally in traffic and could potentially cause a crash. I am requesting that the federal safety agency document and investigate this engine failure as a potential safety defect involving the GM 6.2L L87 engine. I am also requesting that the federal safety agency determine whether 2025 GMC Sierra 1500 vehicles equipped with this engine should be included in an appropriate safety recall or other corrective action. The vehicle is a 2025 GMC Sierra 1500 Denali with approximately 35,000 miles. The engine failure and warning lights occurred during normal vehicle operation. The vehicle and repair records can be made available for inspection, and I can provide dealer repair orders, diagnostic information, photographs, and other documentation concerning the failure. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Aug 21, 2026 · Engine, Transmission · FL

On July 25, 2026 when starting my vehicle, it began to shake violently and I receive numerous errors, including a check engine light and displays in the infotainment, indicating there were engine and transmission errors with the vehicle. I received a text message notification and in app notification from GMC indicating that there was a critical error and provided error code P0352. This appears to be an error related to a faulty engine, this is the 6.2L V8, which is known to be problematic by GMC. Had this happened while I was driving on the interstate three minutes later, it could’ve resulted in great bodily harm or death to both myself and the general public around me. GMC was later able to reproduce the issue at the dealer, confirming the faulty equipment on the vehicle with less than 16,000 miles on it. The component was replaced by the dealer, however, the vehicle is available for inspection.

Filed Aug 13, 2026 · Transmission · MA

Truck vibrates at speeds from 25-45 mph while maintaining speed