GMC Sierra HD AT4 models are off-road-oriented variants that combine enhanced capabilities with GMC’s premium refinement to practically complement an authentic outdoor lifestyle
The performance-enhanced pickups made their debut with arrival of the fourth-generation Sierra HD model, and are expected to receive a refresh for the 2023 model year.
| Model Year Availability | 2020 – Present | |
| Engine(s) | 6.6L L8T V8,6.6L L5P Duramax | |
| Transmission(s) | 6-Speed Auto, Allison 10-Speed Auto | |
| Drive Wheels | Four-Wheel-Drive | |
| Availability | U.S.A., Canada, Mexico, Middle East | |
The GMC Sierra HD AT4 debuted for the 2020 model year, when the fourth-generation heavy-duty pickup truck lineup entered the market. Like all AT4 models, Silverado HD AT4 features were highlighted by off-road components, and included:
- Off-road suspension, Rancho Shocks, skid plates, Eaton locking rear differential
- Eighteen-inch wheels wrapped with Michelin all-terrain tires
- 20-inch wheels available
- Traction Select System with specific Off-Road mode
- Hill Descent Control and Hill Start Assist
- Segment-exclusive 15-inch diagonal Head-Up Display with Off-Road Inclinometer
- HD Surround Vision for low-speed views of vehicle surroundings
It’s worth highlighting the fact that all of GM’s heavy-duty pickup offerings are fitted with a standard ride height, meaning Sierra HD AT4 models are not equipped with a lift kit.
For the 2021 model year, the Sierra HD AT4 pickup received a few minor changes, including the addition of the AT4 high clearance step (LPO-level item), high-gloss Black mirror caps, a new AT4 Premium Plus Package, and revisions to AT4 Preferred Package contents.
Notably, the 2022 GMC Sierra HD AT4 sees no changes, though it is expected to receive a refresh for the 2023 model year.
- See detailed 2021 GMC Sierra 2500HD changes, updates and new features here:Â 2021 GMC Sierra 2500HD change log.
- See detailed 2021 GMC Sierra 3500HD changes, updates and new features here:Â 2021 GMC Sierra 3500HD change log.
Discussion
Discuss GMC Sierra AT4 models in our GMC forum.
Sierra AT4 News
This GMC Sierra HD AT4X AEV Edition Is The Ultimate Overland Build 2025
Don't send a van to do a truck's job.
Read More »
Hercules Launches New TIS RT1 All-Terrain Tire, Fits Chevy Silverado And GMC Sierra
Replacement for both 1500 and HD models.
Read More »
