2021 GMC Sierra 3500 problems
NHTSA has received 28 complaints about the 2021 GMC Sierra 3500, and 25% of them involve drivetrain & axles. After that come brakes (18%) and electrical system (14%).
At a glance
- Complaints
- 28 filed with NHTSA
- Most reported
- Drivetrain & axles 25% of complaints
- Crashes and fires
- 0 and 0
- Injuries and deaths
- 0 and 0
Source: NHTSA owner complaints
Where the complaints are
Share of this model year's complaints by the part of the car involved. One complaint can name more than one part, so the shares can add up to more than 100%.
What the data shows
None of these complaints report a crash, fire, injury or death. Its complaints are less severe on average than those of 100% of model years in our database.
Looking only at complaints filed within five years of the model year (so older and newer years are comparable), the 2021 ranks 6th most-complained-about out of 15 model years of the GMC Sierra 3500 with enough data (28 complaints in that window). It is also covered by 5 safety recall campaigns.
What owners wrote
A few complaints as filed, shortened and with personal details removed. The first ones are among the most serious reports for this model year; the rest are typical.
Trailer brake wiring connection continually disconnectsthen reconnects some time later. Some periods of up to 10 minutes without having trailer braking power. Major safety issue when toeing fifth wheel trailer. We lost brakes going down steep grades. GMC is aware of issue, but has not provided a solution. Vehicle has been yo service shop with no resolution. Case has been opened with GMC.
The vehicle recently had a recall repaired at the dealership. I subsequently took delivery on it as a BRAND NEW UNIT, and the brakes are extremely soft; to the point where I must depress the pedal to the floor to get it stopped even at slow speeds. I hoped it was just an air bubble from the repair; but the fluid levels are full and the dealer had no ideas on what could be wrong at this point. I have a great relationship with this dealer, and we’ll continue working on it.
The contact owns a 2021 GMC Sierra 3500. The contact stated that while his wife had the vehicle idling with the rear defroster activated, shortly afterwards, she observed smoke coming from the plastic on the rear sliding window. After a visual inspection, the contact's wife observed that the plastic was melting, prompting her to deactivate the rear defroster. No warning lights were illuminated. The vehicle was taken to the dealer, who was unable to determine the cause of the failure. The vehicle was not repaired.
The contact filed the complaint on behalf of the owner of a 2021 GMC Sierra 3500. The contact stated that while the vehicle owner was driving at an undisclosed speed, the driver noticed that the rear wheels were attempting to lockup. The contact stated that the failure was noticeable while driving forward and while reversing. No warning light illuminated. The vehicle was taken to the independent mechanic, where it was diagnosed with detached rear brake pads and detached rear emergency brake shoes.