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
GMC Sierra AT4 1500: Refreshed vs. Pre-Refresh Trucks Side By Side
Carefully looking over the fascia design differences.
Read More »
Little-Known GMC Accessory Kit Gives Sierra AT4 Owners Black Badges
And it should be available as a factory option.
Read More »
