GMC Complaints

Engine making noise during a trip took to dealership and they reported engine is bad and needs to be replaced because it would freeze on the road. Vehicle has 7000 miles.

On XXX around noon in medium traffic I was traveling on the [XXX] southbound at about 65 miles per hour when the engine suddenly stopped with no warning. To make matters worse the dash instructed me to apply the brake to start?? Not at 65 mph! I was able to coast onto the offramp safely and call for a tow to the GMC dealer in [XXX]. They diagnosed the failure to the engine seizing. I was fortunate to pull off the freeway as being an experienced driver for more than 50 years although it would be anyone's opinion that a less experienced driver could have been injured or worse. My fear is that the replacement engine that GM will install again have the same problem at any time in the future with no warning and I or my family will not be as fortunate the next time. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Driving approximately 75mph on a local highway, my engine shut down with no warning, the screen said to shift into neutral to restart but nothing happened so I was stranded along the side of the highway and had to wait 2hrs for a tow truck in the middle of the night and the engine is currently locked up.

My vehicle "passed" the engine recall only to have the engine blow at 33,000 miles. My vehicle was at the dealership for 52 days most of the time was spent waiting for the new engine. Dealership was amazing, GMC however is the worst. My new engine has about 1,000 miles on it and it stutters occasionally when the auto start turns on.

ENGINE STARTED KNOCKING AT 18K MILES AND TOOK TO DEALER AND THEY FOUND METAL IN THE FILTER AND INSTALLED A NEW ENGINE AND ALSO REPLACED THE MIDPLATE GASKET ON THE VALVEBODY DUE TO A HARSH DOWNSHIFT WITHOUT CODES IN THE SYSTEM THIS ENGINE IS GOING ON 2K MILES AND IT SEEMS TO BE FINE NOW BUT THE PROBLEM WITH 6.2 WAS ONLY SUPPOSED TO BE ON THE 21-24 MODELS AND MINE IS A 25 MODEL AND ALREADY HAD A REPLACED AND NOTHING FROM GM WAS SAID TO EXTEND THE WARRANTY ON THIS MODEL AND POWERTRAIN

Two problems with this vehicle: 1) Transmission occasionally slips on the 2-3 shift which the dealer says he cannot duplicate. Vehicle was brought in four times for this problem. According to the dealer GM corporate has stated the transmission is working within normal parameters, since no codes were found. 2) Vehicle auto braking randomly slams on the brakes with nothing in its path. Dealer states turn off system to just Alert only not Alert and Brake. No codes were set. Fortunately no one was behind me as this could have caused me to be rear ended by another vehicle. In both cases it appears that if no codes are set the problem does not exist. Nov. 21, 2025, Feb. 12, 2026, July 09, 2026, Aug. 28, 2026.

The vehicle was delivered from the factory with a severe size mismatch between its primary rolling stock and its emergency spare tire. The truck features factory-installed 20-inch wheels and tires but was manufactured and shipped with an undersized 18-inch spare tire assembly secured underneath the bed. On a heavy-duty 3500-series truck built for heavy towing and hauling, utilizing a drastically different tire diameter during an emergency road event forces the rear differential and transfer case to spin at mismatched speeds. This creates an immediate risk of sudden mechanical drivetrain failure, loss of vehicle control, or compromised braking stability while operating under load on public highways. Consumers relying on factory equipment during emergency roadside scenarios should not be exposed to hidden mechanical hazards due to factory assembly omissions. Upon discovering the factory defect, the local dealership attempted remediation by supplying a shop take-off wheel and an aged, three-year-old tire (DOT 2223). This highlights that while individual dealerships scramble to fix these factory omissions with makeshift inventory, consumers purchasing new heavy-duty vehicles are still absorbing compromised, aged safety equipment due to lack of manufacturing quality control. I have also filed a complaint with GM and have requested immediate remediation with a correct new tire and wheel and am waiting for a response.

The vehicle was delivered from the factory with a severe size mismatch between its primary rolling stock and its emergency spare tire. The truck features factory-installed 20-inch wheels and tires but was manufactured and shipped with an undersized 18-inch spare tire assembly secured underneath the bed. On a heavy-duty 3500-series truck built for heavy towing and hauling, utilizing a drastically different tire diameter during an emergency road event forces the rear differential and transfer case to spin at mismatched speeds. This creates an immediate risk of sudden mechanical drivetrain failure, loss of vehicle control, or compromised braking stability while operating under load on public highways. Consumers relying on factory equipment during emergency roadside scenarios should not be exposed to hidden mechanical hazards due to factory assembly omissions. Upon discovering the factory defect, the local dealership attempted remediation by supplying a shop take-off wheel and an aged, three-year-old tire (DOT 2223). This highlights that while individual dealerships scramble to fix these factory omissions with makeshift inventory, consumers purchasing new heavy-duty vehicles are still absorbing compromised, aged safety equipment due to lack of manufacturing quality control. I have also filed a complaint with GM and have requested immediate remediation with a correct new tire and wheel and am waiting for a response.

Had a check engine light come on a couple months ago and vehicle went into Reduced Accelaration safety mode. Come to find out, it was a faulty Valve Body. I came out of pocket for $2,800 to get it replaced because GMC said the Valve Body/Special Coverage was not assigned to this VIN. Even though it was a 2022 with 60,000 miles on it fitting every criteria of the exact recall (mind-blowing). Now fast forward to now, the same check engine light and reduced acceleration fault is active associated with a Transmission Control Module Fault. This truck is entirely too new and taken care of to be dealing with these types of major issues. It’s been a severe inconvenience for my wife as it’s her daily driver. To make matters worse, the lack of support and assistance from GMC has made us go from very loyal customers and supporters, to now seeing how quickly we can get away from this disaster of a vehicle and Customer Service.

FROM DEALER ASSESSMENT Concern - CUSTOMER STATES WHEN VEHICLE IS ACCELERATING THERE IS A RATTLE Correction - test drove and was able to duplicate rattle/knocking from the engine. checked oil level and condition verified both are good. checked for bulletins and followed 23-NA-170. compared vehicle noise to noise is video and noise is nearly identical. removed oil filter and inspected for debris, found heavy amounts of metal debris present in the filter. performed crankshaft end play mesasurement and found that the crankshaft end play is way over spec at 1/4 of an inch. recommend replacing the engine assembly per bulletin Parts) 1x ENGINE 2x (S)GASKET $0.00 $0.00 6x (S)BOLT 1x BOLT 1x exhaust pipe connector gaskets both sides $0.00 8x (S)GASKET 1x fuel feed pipes all $0.00 1x (S)SEAL KIT 1x (S)GASKET $0.00 1x (S)SEAL 1x W-(S)RADIATOR $0.00 1x (S)HOSE 1x coolant $0.00 1x oil filter 1x oil $0.00 Approved 2026-08-18 Labor: $0.00 Parts: $0.00 $0.00 $0.00 $0.00 $0.00 $0.00 $0.00 $0.00 Subtotal Line B: $0.00 *Subtotal is before Shop Charge and Taxes