2025 GMC Sierra 1500: sudden loss of power

Filed Nov 2, 2026 · Engine · MD

Was about 1 and a half hours into my 8 hour trip home, when I started to hear a clanging sound coming from my engine after I passed a slow moving RV. The truck ran for about 20 additional minutes when it lost power and shut off. Mileage was at a little over 16,000 miles. No warning lamps, messages or other symptoms of the problem prior to the failure. I was fortunate to be pulling into a parking lot when it shut down, GMC roadside assistance had my truck towed to a GMC dealer where it was determined the engine was blown. They replaced the engine.

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 29, 2026 · Engine · 64,000 miles · NC

The contact owns a 2025 GMC Sierra 1500. The contact stated that while her husband was driving 10 MPH, the vehicle lost power. The driver turned off the vehicle and attempted to restart the vehicle; however, the vehicle failed to respond. No warning light was illuminated. A dealer was contacted. The vehicle was towed to the dealer where it was diagnosed and determined that the engine needed to be replaced. The engine was replaced and the vehicle was repaired. The contact stated that the engine was replaced twice. The manufacture was notified of the failure and opened a case. The approximate failure mileage was 64,000.

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 17, 2026 · Engine · AZ

Vehicle lost power. Pulled into parking lot steering wheel locked. Tried to restart truck nothing happened. Took to dealer they said motor needed to be replaced and it would take 4 to 6 weeks.

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 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 Jul 7, 2026 · Engine · ID

What component or system failed or malfunctioned, and is it available for inspection upon request? The engine/powertrain failed. The vehicle is a 2025 GMC Sierra 1500 equipped with the 6.2L V8 engine. The engine developed a severe knocking noise and loss of power at approximately 5,545 miles. The vehicle was taken to the GM dealership, where an engine replacement was approved. The failed engine/component may be available for inspection through the dealership or GM, depending on whether it has already been removed or returned to the manufacturer. How was your safety or the safety of others put at risk? The engine failure created a safety concern because the vehicle experienced reduced power/loss of propulsion while being operated. This could have put me and other drivers at risk because a sudden loss of engine power can make it difficult to safely maintain speed, merge, tow, or move the vehicle out of traffic. The issue occurred at very low mileage and without enough warning to prevent the failure. Has the problem been reproduced or confirmed by a dealer or independent service center? Yes. The problem was confirmed by a GM dealership. The dealer diagnosed the engine failure and GM approved an engine replacement under warranty. Has the vehicle or component been inspected by the manufacturer, police, insurance representatives or others? The vehicle was inspected by the GM dealership. GM was involved in approving the engine replacement under warranty. To my knowledge, the vehicle has not been inspected by police or insurance representatives. Were there any warning lamps, messages or other symptoms of the problem prior to the failure, and when did they first appear? Prior to the failure, the vehicle developed a severe engine knocking noise and reduced power/lack of power. These symptoms appeared shortly before the engine failure at approximately 5,545 miles. I do not recall any specific warning lamps or messages before the failure, unless the dealership records

Filed May 15, 2026 · Engine · GA

My GMC sierra AT4 with the 3.0L Duramax Diesel, has 1,500 miles on it, when the engine failed. I was traveling from [XXX] to [XXX] , towing a trailer, when the check engine light came, and the truck entered reduced power mode. It immediately slowed the truck without warning - which made for a very dangerous situation for all of the vehicles behind me and for my vehicle. After getting the vehicle and trailer to a dealer, disconnecting the trailer, and then getting the truck in the shop, the dealer defined the OBDII code as being P06DD - Engine oil pressure control solenoid valve stuck off. U0146 - Lost communication with central gateway module, and U1605 - Lost communication with side obstacle detection control module - right on private CAN Bus. The dealer indicated that the P06DD code meant that the thrust bearing on the crankshaft failed and the engine would need to be replaced. The ending only has 1500 miles on it. It turns out that there are MANY GM 3.0L diesel engines that have failed for this issue and that GM issued a Technical Service bulletin in 2025 for this issue - TSB 25-NA-307. I work in the medical device industry and when there is a safety issue with your products - you initiate a RECALL. To date there has been no recall simply the TSB. What is the federal safety agency going to do about ensuring that GM, and other manufacturers, are making engines safe? These engines can literally explode - sending metal shards through the engine into the passenger compartment. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Apr 20, 2026 · Engine · IN

I bought a brand-new GMC 1500 6.2L AT4 back in 2025. Never have an engine recall. At 39K miles, lost power, and ended up replacing the camshaft and lifters. 2K miles later went back to the dealer for engine replacement.

Filed Feb 23, 2026 · Engine · MI

2025 GMC Sierra 6.2 L V8 engine failed by locking up or seizing. Heard pinging / knocking sounds while driving 3 miles from my home to the dealer. Engine shut off without warning, vehicle shifted to Neutral. Coasted to a stop, attempted to restart the engine, would only crank. Dealer diagnosis is that the engine will need to be replaced. Sounds just like the 2021 - 2024 GM recall for this same engine. Vehicle has 11,670 miles on it. Safety risk: Loss of ALL power while driving. No Warning lamps or messages prior to engine failure.

Filed Feb 12, 2026 · Engine · MI

2025 GMC Sierra 1500 has had 2 engine failures since purchase date June 2025. Engine failed on a road trip with my family, leaving me stranded for hours. After the problem being resolved, engine failed once again after 5 months. On the dash it said loss of power and wouldn’t crank to turn ON