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What 49 owners told NHTSA about the 2021 GMC Sierra 2500 Hd

These are the actual owner complaints behind this car’s reliability verdict, filed with the federal government, unedited. They’re unverified reports, not confirmed defects: read them as leads for your pre-purchase inspection, not a diagnosis.

All (49)Crash / fire / injury (4)Transmission & drivetrain (12)Lights (9)Engine (8)Electrical system (6)Body & structure (5)Brakes (5)Latches & locks (4)Driver assistance (3)Airbags (2)Backup camera & sensors (1)

1 of 49 complaints match · Transmission & drivetrain · crash/fire/injury only · clear filters

Oct 29, 2025Transmission & drivetrainCrash1 injury

The contact owns a 2021 GMC Sierra 2500. The contact stated that while driving at 50 MPH, the contact was pulling a trailer that he had loaded, and he drove around a curve, the gear shifted down independently, and the trailer pushed the vehicle off the right side, causing him to crash into a post and embankment. The contact mentioned he was able to shift the gear into Four Wheel Drive to get back on the road. The contact mentioned he pulled over to the right side of the road, exited the vehicle to inspect, and noticed damage to the vehicle and the trailer. The contact stated no air bag deployed. The contact stated that he sustained injuries left arm and neck, causing his muscles to tighten. No medical attention was required. The contact stated no police report was filed. The contact mentioned that the vehicle was previously repaired for a manufacturer's recall with the transmission, but failed to prevent the failure. The contact was relating the failure to NHTSA Campaign Number: 24V797000 (POWER TRAIN). The vehicle was serviced by the dealer, but the remedy failed to repair the vehicle. The contact stated that the failure was not diagnosed by a dealer or independent mechanic. The manufacturer was not notified of the failure. The approximate failure mileage was 78,000.

NHTSA ODI 11696338

Working with the data? Download all 49 complaints as CSV · fetched from NHTSA July 19, 2026

How to use these: a complaint is one owner’s report, filed voluntarily and published unverified. Patterns matter more than any single story. If several owners describe the same failure at similar mileage, put that system at the top of your pre-purchase inspection list. Back to the full 2021 GMC Sierra 2500 Hd verdict →