2025 GMC Sierra 1500

was driving truck and reduced acceleration drive with care comes up on dash pull over shut truck off start truck warning gone in 30sec back on and repeat drive off again then truck shut off while driving and try to start again and the dash went black motor did not turn over then tried again and same thing called tow company and had towed to dealership. dealership said it had 2 pages of codes and now needs a new motor........ no estimated time on getting my truck back

I was driving and the engine abruptly stalled. The truck self-shifted to Neutral. Once stopped, I shifted to Park to attempt a restart. It would not crank. I was on a 2-lane road so I did not have a shoulder. Once I realized it would not restart I tried to shift to Neutral so I could push it to a subdivision road about 50 yards away only to find out my transmission has no ability to shift to Neutral (the dealer confirmed this later). So I was stuck on the road for hours just over the crest of a hill with people coming up on me and my family at 50mph. It was a windy 10 degrees so we could not wait on the side of the road where we would have been safer. This is how people get killed; being stopped where people can't see you and do not expect you to be stopped. Why can I not get the truck off the road? If this happened on an 8-lane highway how would I get to a shoulder, even after traffic had stopped behind me? On top of all that, the problem with the truck ended up being an engine bearing failure (per the dealership service dept) that is a known problem with this engine and truck build date. General Motors needs to proactively diagnose and get these engines replaced before someone gets hurt. There is a TSB issued for the bearing issue but when I asked my dealer about it a month ago, before the failure, they acted like they knew nothing about it and told me to bring it in if I hear noises. If they had offered to check the crankshaft endplay when I asked about it ( as the TSB suggests), I may not have gotten stranded and my family's safety put at risk. There were no warning lamps, and no strange noises before the engine seized. My fuel economy had decreased by about 20% in the last month but that may be from cold weather operating conditions. I have a separate electrical issue that I've been chasing down and I assumed this stall condition was related to that. But the dealer confirmed this was a bearing failure.

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)

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.

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.