2020 GMC Sierra 3500 problems & reliability
51 owner complaints filed with NHTSA for the 2020 GMC Sierra 3500, alongside 8 safety recall campaigns. Last verified Aug 7, 2026. Complaints are unverified reports submitted by owners to the federal Office of Defects Investigation.
Each complaint is counted once (by NHTSA case number), even when it names several vehicles.
1 complaint report injuries (4 injured).
Most reported problems
| Component | Complaints | Share |
|---|---|---|
| Power Train → | 19 | 37% |
| Electrical System | 9 | 18% |
| Service Brakes | 7 | 14% |
| Engine | 6 | 12% |
| Unknown OR Other | 6 | 12% |
| Fuel/propulsion System | 5 | 10% |
| Structure | 5 | 10% |
| Tires | 4 | 8% |
| Air Bags | 1 | 2% |
| Engine and Engine Cooling | 1 | 2% |
Component groups as classified by NHTSA. A complaint can name more than one component, so shares may sum to more than 100%.
All 19 reported components →Complaints by incident year
What owners report
“My truck has been exhibiting hard downshifting at certain speeds, when the powertrain loads up such as a grade change, and requires a downshift. I have complained about this issue to the dealership as early as 2022, and 33,185 miles. The dealership made me pay for a transmission $388.90 flush which did not resolve the…”
Power Train · filed Mar 20, 2026
“Known defect with 2019 and now 2020 GMC sierra trucks. Design was updated for 2021+ which has corrected the seal failure defect. GM has issued a service bulletin to dealers about how to repair the problem. Back window is leaking water. Defective seal noted by GM. GM is only covering the cost of repair if. Vehicle is…”
Structure · filed Oct 16, 2025
“the engine seized at 65mph. available for inspection. was left stranded in a limited access area with no cell service. there was no warning, the engine just stopped at highway speed and would not restart. the problem was confirmed by an independent service center. they couldnt identify which component had failed…”
Engine · filed Oct 8, 2025
Verbatim excerpts from complaints filed with NHTSA. Reports are not independently verified.
Federal defect investigations
- Air Bag Malfunction
Preliminary Evaluation PE21010 · opened Apr 9, 2021 · closed Aug 24, 2023
Technical service bulletins
901 manufacturer communications (TSBs, service campaigns, warranty extensions) are on file with NHTSA for the 2020 GMC Sierra 3500. The 10 most recent:
This PI provides information to repair the door water deflector which is not sealed properly allows water into the door jam/sill area.
PIT5680B · Service Bulletin/Repair Instructions · issued Jul 23, 2026
PI to help diagnose A/C concern
PIT5099J · Service Bulletin/Repair Instructions · issued Jul 21, 2026
This PI provides diagnostic tips for diagnosing electric trailer brakes issues.
PIT5509N · Service Bulletin/Repair Instructions · issued Jul 21, 2026
This PI was created to help avoid unnecessary front camera module replacements
PIT6473F · Service Bulletin/Repair Instructions · issued Jul 17, 2026
The purpose of this PI is to inform dealer technicians of a normal cab pressure relief valve noise to avoid unnecessary part replacement
PIT6532 · Service Bulletin/Repair Instructions · issued Jul 6, 2026
This Preliminary information communicates information on a hydraulic rush type noise from the power steering gear. This noise is a characteristic of the new Active Hydraulic Assist System RPO NV8 and no repairs should…
PIT5544J · Service Bulletin/Repair Instructions · issued Jun 24, 2026
This PI provides diagnostic steps for dealer technicians to verify the condition and ensure that part replacement is necessary
PIT6523 · Service Bulletin/Repair Instructions · issued Jun 10, 2026
This PI provides diagnostic tips for diagnosing electric trailer brakes issues.
PIT5509M · Service Bulletin/Repair Instructions · issued May 14, 2026
This Preliminary information communicates that some customers may comment that after an auto-stop event the engine does not restart and to inspect the engine ground strap. Temporarily on hold while PIE0572 is active…
PIT5689N · Service Bulletin/Repair Instructions · issued Apr 13, 2026
This preliminary information communicates information about how to determine if a wheel and tires size change is available.
PIT3271Q · Service Bulletin/Repair Instructions · issued Apr 1, 2026
TSBs are repair guidance manufacturers send to dealers — they are not recalls and repairs are not automatically free. Full documents are available on NHTSA’s site.
Safety recalls
The 2020 GMC Sierra 3500 has 8 NHTSA recall campaigns — recall repairs are free at franchised dealers regardless of the vehicle’s age.
Check whether your specific vehicle is affected
Recall campaigns often cover only certain VIN ranges. Enter your VIN on the official NHTSA site to confirm whether your vehicle is included and whether the repair is still open.
Check VIN on NHTSA →Buying a used 2020 GMC Sierra 3500?
- · Decode the seller’s VIN with our free VIN decoder to confirm the exact year, engine and trim.
- · Check for unrepaired recalls by VIN on NHTSA’s official lookup — recall repairs are free.