2026 GMC Sierra 1500 Engine problems

Engine knocking and failure

See attached document for complaint.

Three different times now (most recent: 10/22/2026), I have had my truck completely shut off when coming to a stop on the highway/interstate. I always have auto start/stop disabled when I drive. When it happens, a message shows on the dash that says press start button. No other codes or check engine light. Thankfully it has started every time, but this is obviously a serious safety concern. After the second time it happened, I had the dealer (Woodhouse Buick GMC Omaha) look at it on 9/14/2026, but they couldn't...

While driving the truck it randomly shuts down, message on dash says shift to park to restart. No check engine light comes on or any other message. When it does this, the truck goes into park. It has been to the dealership 3 times and has not been fixed!

I had driven about 30 minutes on the Interstate at highway speeds and had just exited the Interstate and the truck made a horrible noise, shut off, and the transmission threw itself into park at about 10 mph. At this time, the engine did not want to restart, but did eventually and I had a check engine light on, but I was able to move the truck out of the intersection so that I could be towed to the dealership. Prior to the incident, there were no check engine lights and the vehicle had only been serviced at a GMC...

I am writing to formally request that General Motors repurchase my 2026 GMC Sierra 1500, currently with approximately 9,445 miles, due to a serious and unresolved mechanical defect that poses a significant safety risk. Since purchasing this vehicle, I have experienced four separate incidents involving a complete and unexpected loss of engine power, causing the truck to become inoperable. In each instance, the vehicle suddenly lost propulsion and came to a stop without warning. While three of these events occurred...

On 10/15/2026 I was making a slow right-hand turn up a slight incline into a parking lot when the vehicle braked very hard and the transmission made a grinding noise. I looked at the dashboard, and it was showing that the truck shifted into park while I was driving. The electronic brake engaged as well. I tried putting the truck back into drive, but it would not go into drive. On the dash there was a Service Transmission warning. The push to start engine button still had the green LED on as if the vehicle was...

I was approaching an intersection about to make a left turn as the turn signal was flashing yellow and my truck just stopped accelerating. If i had taken that turn i would have got hit and most likely cause a huge pile up because the amount of traffic going through. I put my hazard lights on and tried shifting my truck into park, and then back into drive, and it would not accelerate. I had to turn my truck off and on a few times for it to accelerate. There were no warning lights on my dash and the truck is brand new.

5/08/2026: I stopped outside my garage. I then placed the truck in park and exited the vehicle while running. I went inside my garage and several minutes later, heard a crash. The truck had driven forward while unattended, and crashed into the corner of my garage, causing damage to both the building and the truck. Truck indicated it was still in park upon reentry. 5/11/2026 In a separate incident 3 days later, while driving at approximately 50mph, truck engaged in an automatic braking event with no discernible...

We bought the vehicle on February 28th and on March10th my husband was driving on his way to work on the I95 highway and the engine shut down. My husband was in the middle of the highway with a speed limit of 65. Traffic was able to slow not to cause any more accidents however he had to be towed and GM replaced the engine. Because it had not been 30 days in the shop. Due to GM abiding by Lemon laws we were not able to qualify for a buy back. We have been fighting with them ever since. I was able to get a...

Engine had catastrophic failure at only 1,433 miles driven. Incident happened on the interstate and truck was required to be towed to the dealer. Dealer said engine replacement is necessary.

While driving on a public road, the 6.2L L87 V8 stalled without warning. There was heavy smoke and an oil trail of about 300 yards behind the truck. The engine would not restart, and the transmission would not shift into neutral. The truck was moved a short distance off the road and towed the next day to the selling GMC dealer. Odometer was 4,663 miles. Oil life remaining was 38 percent. The truck was stock, with no modifications, and was operated on premium fuel. No warning lamp was noticed before the stall. The...

On September 29, 2026, I was driving my GMC Sierra 1500 on the highway at approximately 15 mph due to construction when the truck suddenly lost acceleration. Engine warning messages appeared, the vehicle automatically shifted into neutral, and the engine completely shut off while I was driving. A message instructed me to restart the engine. I attempted to restart it, and the truck eventually turned back on, although it was difficult to start. I was able to carefully drive the vehicle home. This was extremely...

The 6.2L engine died at 8,300 miles. It took the dealership 6 weeks and would not give me a repurchase lease buyback. They put a new engine in, but I'm hearing that they didn't really fix the problem and this is just a new version.

The powertrain/transmission is malfunctioning. The vehicle shutters, vibrates, and surges forward when coming to a stop, as if it wants to take off on its own. These symptoms began within the first couple of days after purchasing the vehicle on [redacted]. The valve body was replaced, but the issue continues. The vehicle is available for inspection. GM Case Number: [redacted] Dealership TAC Case: [redacted] This creates a serious safety risk. When stopping, the truck shutters and unexpectedly tries to lunge...

Dealer confirmed 6.2 V8 engine failed at a little over 4000 miles. Dealer stated it was the bottom of the engine. Probably the same failure the 21-24 recall is for.

I was driving home on the evening of September 12th 2026 and when I exited the interstate and came to a stop at the traffic signal my vehicle died and I had to have it towed. There was no way to flat tow because we couldn't get it into neutral without the vehicle's engine running. Once the vehicle's engine died it would not restart. Had this happened while still on the interstate causing my vehicle to be disabled in the lane of travel it could have been deadly since it was 10 p.m. in the evening and dark outside. Anyhow had the vehicle towed to the dealership for diagnosis and the engine spun #7 rod bearing which ruined the entire engine at just 15,182 miles.

Truck was sold to me and the dealership said the truck did not have the defect and the oil was changed to a thicker oil as a precaution. 4,000 miles later the engine failed, was diagnosed as catastrophic engine failure due to the known recall, and was replaced, new engine is now making the same rod knocking noise.

I purchased this vehicle on May 28th 2026. At that time I was told there were no problems with the 6.2L engine. The problems they have had didn't affect the 2026 Denali 1500 6.2L's. After hearing about numerous 25's and 26's engine failures I decided to have my first oil change at 1540 miles. I asked the dealership to give me the oil filter so I could open it and examine it. I found excessive metal in the filter, indicating to me that the engine is failing. I contacted the dealer, they told me to go to GM Customer...

2026 GMC Sierra 1500 Denali 6.2L , with 3550 miles; started ticking and another mile to get home started knocking, had truck for less than a month, had it towed to the dealer they said will get a new engine, they can't even five me a time frame for the new engine replacement.

2026 GMC Sierra 1500 Denali 6.2L , with 3550 miles; started ticking at 45 MPH and another mile to get home started knocking, had truck for less than a month; no warning lights. I had it towed to the dealer. They said it needed a new engine, no time frame for repair.

With 10000 miles on my 6.2 liter the engine failed. Cause was main bearing failure. Needed full engine replacement.

2026 GMC Sierra SLT with 3.0 Duramax diesel engine. While driving down the road with the cruise set to 55 MPH on 8/29/26, the engine started to run rough. I slowed down, but this did not seem to help; I sped up, and the problem persisted no matter what I did. Service traction control and service ESC displayed on the dash. I drove to the dealership; their service department was closed because it was Saturday. I took my salesman for a ride so he could witness the issue firsthand. He confirmed something was not right,...

While turning right and at a slight incline the truck engine turned off, the transmission made a grinding noise, the truck went into neutral and the dash stayed "Press Start Button". This is the second time this has happened within 5000 miles of the struck being purchased. Several others have reported the exact same issue on Facebook forums.

The contact owned a 2026 GMC Sierra 1500. The contact stated that while accelerating from a red light at 15 MPH, the vehicle sputtered and shook before finally moving forward. The contact stated the failure was a recurring failure. The contact associated the failure with NHTSA Action Number: EA26005 (ENGINE). The dealer was contacted. The failure mileage was approximately 160.