GMC Complaints

transmission has been replaced, still having same problems. Actuator was fixed within the transfer case. still shaking. was driven by dealer and told to check again after changing into summer tires. changed into summer tires and still having issues if not worse. separately; the power running boards have never worked - been told its wiring issue. wiring issue is a concern for fire safety.

The transmission has always been rough. It has now gone out at 75,000 miles. This transmission issue really seemed to get worse about 50,000 miles. But when I called the dealer, they said they were backed up and couldn't get to it for 9-12 weeks (Covid excuses at that point). Then, it really had an issue going down a large grade into [XXX] . But the issues seemed fairly intermittent. I had an independent shop who said it was hard to tell if it was intermittent. They didn't find metal shavings at the time. ADDITIONALLY, it has also always been a little rough driving. A mechanic looking at it today told me there are no sway bar links at all. This truck has not been modified. This had to have come off the line faulty. Among all the other things. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

So the shock strut system up front has a grommet that holds it in. The repair order said they put a shock simulator in the car and it gave false reading saying it was good and it came out broke break line and caused me to jump a curve to stop the vehicle. ALSO Now the THE TAIL LIGHT IS OUT AND NO WAY TO REPAIR IT NO ONE HAS THE LIGHT. Also this car is on its third transmission

The contact owns a 2019 GMC Acadia. The contact stated that while driving at an undisclosed speed, a “Steering Assist is Reduced ” warning message unexpectedly displayed. The contact also stated that the thermostat became inoperable. Additionally, the thermostat information was no longer displayed on the instrument panel. The vehicle was taken to the dealer, where it was diagnosed that the thermostat had failed and needed to be replaced. The vehicle was not repaired. The manufacturer was made aware of the failure and referred the contact to the NHTSA Hotline for further assistance. The failure mileage was approximately 48,500.

The vehicle experienced repeated failures involving the Electronic Stability Control (ESC), Traction Control System, and Check Engine system. Warning indicators for the ESC, traction control, and check engine illuminated while operating the vehicle. The issue has occurred on two separate occasions. The first incident occurred on May 4, 2026. The vehicle was taken to the dealership for inspection and repair, and the dealership advised that the issue had been corrected. However, the same problem reoccurred on May 7, 2026. The vehicle has been inspected by the dealership service department, and the malfunction was confirmed. The affected components and vehicle are available for inspection upon request. The failure created a significant safety concern because the ESC and traction control systems are critical safety features designed to assist with vehicle stability, traction, and driver control, particularly during emergency maneuvers or adverse road conditions. The warning indicators raised concerns that the vehicle could unexpectedly lose stability assistance, traction management, or engine performance while driving. This placed the driver and others at risk because the vehicle’s ability to respond safely during normal or emergency driving conditions could have been compromised. The repeated recurrence of the issue, even after dealership repair attempts, raises concern regarding the reliability and effectiveness of the corrective action performed.

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 NHTSA 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)

For the last 6 months, I keep getting a "shift to Park" message on my dashboard indicating that my vehicle is not in park (in which it is). The problem is getting wors, so I called GMC on 5/14/26 to inquire and was informed that my VIN number WAS not include in the resent class action lawsuit for this issue. I then found out by searching myself on line for other complaints that GMC is very aware of this situation and yet refuses to fix the issue free of charge to customers. According to TSB 19-NA-206, t does list my year , make and model of vehicle affected by this faulty part. On 5.15.26, I called the dealership to inquire and was informed that my VIN was not covered under warranty (which I had already known), and that that service I would have to pay lots of money out of pocket for it. The service tech did look in the system and claims (without me even knowing that they had did that repair already....He lied I'm for sure). I informed him well if they did repair that part, and I'm still getting an error message about the same thing, clearly its faulty and the dealership should be responsible for fixing it. This was not the case as I was informed it would have to be out of my pocket. This mess is unfair! GMC is well aware of this faulty pat on vehicles, and to refuse to fix it free of charge is just down right hurtful! GMS is responsible for repairing this part on everyone's vehicle as it is a hazard to everyone and the community to have a vehicle unstable to be able to slide away from a parked position. This is such a road hazard, something has to be done about it. It's not far that I am expected to pay for these faulty wiring costs out my pocket when its a faulty issue GMC is very well aware of.

My engine ticks, and during the winter, I noticed white smoke coming from exhaust pipes in cold and warm weather. I believe there may be an issue with my engine. My vehicle is not on the list provided, and I’m concerned that the dealership responsible for my oil change package will not identify the problem, possibly because newly hired mechanics may lack the experience to make an accurate diagnosis. I’m afraid my vehicle will be overlooked intentionally.

The front grille deflector on my GMC Sierra flew off my truck on a windy day, hit my windshield hard but luckily did not crack it. A vehicle behind me did swerve out of the way to avoid the flying grille deflector but no accident luckily occurred. The piece is damaged but I was able to recover it. I had called the dealership I bought this vehicle at ( around June of 2025) they had confirmed this recall was “fixed” a few months prior to my purchase of the vehicle. Question from me would be, would my local certified GM dealership be able to provide this recall fix? I do not necessarily like the idea of taking back a potential highway safety hazard 2 hours away from my home on the interstate 70 mph back home once this is fixed / repaired with glue/ epoxy that may need 24-48 hours of drying time to cure. Also how can I trust the dealership who “fixed” this issue for it not to happen again?

I recently purchased my vehicle from Big Star Dealership in Baytown Tx. At a little over 1000 miles i was towing a camper. The vehicle stalled, fuel pouring from engine. It was towed and repaired due to fuel pump failure. At a little over 3000 miles the vehicle would not start. Dealership initially said water contamination then changed it and said gasoline contamination and now they say DEF contamination. The vehicle stalling the first time almost caused me to wreck the vehicle