2025 GMC Sierra 1500

I have the 6.2 L87 with the 10 speed transmission in my 2025 Sierra. At cold start, when auto stop restarts the truck, when the truck downshifts under 20 mph down to 12 mph the engine or transmission makes a chirping/squeak/squeal sounds. Several repair attempts have been made, parts replaced. According to GM and their “field engineer” this is a “normal characteristic of the dfm system”. They claim that it has to do with ignition timing. Not my first dfm truck, but it is the first to make this noise. There is not very many components in “the dfm system” that can make a metal on metal squeak/chirp/squeal sound other than lifters/pushrods, but the noise could be coming from the transmission/bell housing area. I am fairly certain this is an early warning sign of engine or transmission failure. Truck currently has 7,800 miles. If this was an actual “normal behavior” for this engine, all of them would make the same noise. But out of 7 other trucks with the same engine and transmission that i have started/drove, none of them made the noise. It has made this noise since i purchased it brand new. A Gm field engineer “looked” at the truck 3 weeks ago, and I still have not received any paperwork on what they actually did when diagnosing it. Not a single document from the dealership or GM, regarding the 4 days that my truck was at the dealership on the 4th repair attempt. Gm technical service bulletin I was referred to by the dealership is 22-NA-218 Will update this complaint when failure occurs.

I bought my truck new in June 2025. On the night of December 29, 2025, with around 9,300 miles on the odometer, I began to hear a knocking sound coming from the engine while I was driving it back to my house from my mother's house. The sound got progressively louder and louder. The truck eventually displayed a "reduced acceleration drive with care" warning. I thought catastrophic engine failure was imminent and did not believe I could make it home. I called my in-laws (they were closer to my location than my house), agreed to park it there overnight, and thankfully made it to their house. The next day the truck was towed to the GMC dealership. A week later, GMC diagnosed this issue as a thrust bearing/crankshaft issue and agreed to replace the entire engine. A crankshaft issue in a new diesel engine should not occur, yet it did. My vehicle is currently being repaired, so the dealership said they had no repair records to provide me. This is the link to the video of the sound it was making after I made it to the in-laws: [XXX] I had just dropped off my [XXX] child with my mother about twenty minutes earlier. I was extremely close to being stranded on the side of the highway at night in the December cold with a [XXX] baby. Thankfully, that did not happen, but it was a close call. My cousin also has had a similar issue with the exact same make and model of his truck. I believe this engine is not being manufactured according to the design specifications and it is a danger to the public until the manufacturing issue with the supplier is adequately corrected. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Cruise control activates at speeds below 2 mph which frequently happens while turning or parking. The cruise control activates by a toggle on the left spoke of the steering wheel which can be easily bumped while doing low speed maneuvers like parking. When bumping the toggle the cruise indicator shows a set speed of 15mph and the vehicle surges forward trying to attain that speed. Since this occurs while maneuvering to park, it creates a dangerous situation if anyone is nearby and you are unable to react in time. This is an ongoing problem that can be duplicated at will.

With approximately 5,200 miles on my new vehicle, received an error message on the dash while driving on 1/8/2026 that read “Reduced acceleration; Drive with care”. I immediately took the vehicle to a local GM dealership and was informed on 1/9/2026 that due to a faulty thrust bearing (covered under the non-mandatory technical service bulletin 25-NA-307), the entire engine sustained a catastrophic failure and that the engine “tanked itself” and “grenaded itself”. Driving with the reduced acceleration mode active is beyond frightening as it’s very difficult to navigate traffic intersections in time to avoid oncoming traffic. It was also noted that it other cases where this faulty part causes the engine to totally fail, the vehicle becomes unusable at that point. I was informed that a replacement motor is not expected from General Motors for at least 2-3 months as this is becoming a more prevalent issue with certain 2025 Sierra’s with the 3.0 Duramax diesel motor.

The contact owns a 2025 GMC Sierra 1500. The contact stated that while driving at 35 MPH, there was an abnormal knocking sound coming from the engine. No warning lights were illuminated. The vehicle was towed to the dealer, where it was diagnosed with a rough idle code, and that the thermostat coolant housing had failed. The contact was provided DTC codes: B1A76 with failure Code 0X15 (pending), P05D, U0075, U0101, U0146, U020C, U0265, U1614, and U1616, and the codes were active. The vehicle was repaired. The contact picked up the vehicle from the dealer after hours, and when the contact started the vehicle, the abnormal knocking sound was still coming from the engine. No warning lights were illuminated. The contact stated that when the A/C was turned off, the abnormal sound ceased. Additionally, the contact performed the oil changes on the vehicle and noticed that the engine was consuming an excessive amount of engine oil. The contact stated that there were no oil stains on the ground. The contact needed to add oil every 800 to 1,000 miles driven. The vehicle was taken to O'Reilly's Chevrolet, located at 6160 E Broadway Blvd, Tucson, AZ, for a diagnostic test, and it was determined that the air compressor had failed. The vehicle was not repaired. The vehicle remained at the dealer pending the repair. The contact stated that when the A/C was activated, the knocking sound in the engine compartment returned. The manufacturer was not made aware of the failure. The failure mileage was approximately 18,000.

If truck has a “dusting of snow” on it, blower motor for defrost and heat retracts to absolute “low” setting to supposedly protect the blower motor. Have been caught driving in snow, and defrost couldn’t keep up with keeping windshield defrosted due to this behavior. Had to pull over on expressway to clean vents on the cowl from snow in order for the defrost to work properly. According to GM, this is normal behavior. In fact this is extremely dangerous and should be investigated and a recall to repair should be made. Having to pull over to remove snow from the cowl, open the hood to clear the other vents is not safe.

Vehicle purchased 8/31/2025 October 20, 2025 "reduced acceleration" alert while driving on why up a significant grade with no way to pull off to the side of the road. Speed limitied to 35mph. Stopped by dealership pulled PO6DD code. Appointment made for November 12th. November 12, 2025 routine oil change and service noted "unable to duplicate concern on vehicly, currently no P06DD is present only DTC that was found in history was U1643 Lost communications with transmission control module can bus 2. cleared DTCs and test drove vehicle and is operating normal no issues. unable to duplicate." December 4th, 2025 driving on interstate and "reduced acceleration" alert...pulled into nearest dealer and code "P06DD" pulled. December 5th, 2025 returned to home dealership "Found Code P06DD. As per TSB#25-NA-307, checked the crankshaft end play, found the crankshaft has excessive end play. This is an indication of a worn thrust bearing. As per TSB engine Replacement is required." Vehicle currently has 6,800 miles.

I own a 2025 GMC Sierra 1500. The rearview camera is inoperable at night (image is too dark). Brought vehicle into to purchasing dealer with complaint. After service, I was told that there was nothing they could do to correct the issue. I then contacted GMC customer service. They advised to bring the vehicle to a different dealer and upon completion to contact customer service again. I did as advised and took the vehicle to a second dealership with the same result. As you are aware, this is a violation of federal law and a serious safety issue for small children, pets or any object behind the vehicle in the dark. Based on what I have been able to discover there are many people with this same complaint. GM is not addressing this issue and is as unwilling to assist others as they have been to assist me.