Earlier this month, GM Authority explained that it was possible to create a Trail Boss-like version of the fourth-generation Chevy Silverado 1500 light duty pickup truck even if it did not leave the factory as a Trail Boss. GMC fans will be pleased to hear that something very similar also applies to the Silverado 1500’s corporate cousin, the GMC Sierra 1500.
|RPO Code||Sierra||SLE||Elevation 3VL||Elevation 3SB||SLT||AT4||Denali|
|Hill Descent Control||JHD||A||A||-||A||A||S||S|
|Heavy-duty air filter||K47||A||A||-||A||A||S||S|
|265/65R18SL all-terrain blackwall tires||XCK||-||A||-||-||A||S||-|
|LT275/65R18C MT blackwall Goodyear Wrangler DuraTrac tires||R3O||-||-||-||-||-||A||-|
|LT265/60R20 MT blackwall Goodyear Wrangler Territory tires (requires 20-inch alloy wheels)||QFV||-||-||-||-||-||A||-|
|2-speed Autotrac transfer case||NQH||A||A||-||A||A||S||S|
|Off-Road Suspension with 2-inch lift and monotube shocks||Z7X||-||-||-||-||-||S||-|
|2-inch lift kit (GMC Accessory)||A||A||-||A||A||-||-|
- A = Available.
- S = Standard.
- – = Not Available.
The issue here is that many features and equipment fitted to the 2021 GMC Sierra AT4 1500 are also available as standard only on the range-topping Denali trim level, or in some cases on no other trim level at all. This can be seen in the table above, or more clearly in the following list:
- Hill Descent Control (standard on AT4 and Denali)
- Heavy-duty air filter (AT4 and Denali)
- Dual exhaust (AT4 and Denali)
- 2-speed Autotrac transfer case (AT4 and Denali)
- Skid plates (AT4 only)
- Off-Road Suspension with 2-inch lift and monotube shocks (AT4 only)
Most of these features can be ordered as part of the X31 Off-Road Package on the GMC Sierra in the Sierra base, SLE, Elevation 3SB and SLT trim levels, though not on the lease-focused Elevation 3VL or the range-topping Denali.
Pricing for the X31 Off-Road Package ranges from $850 to $1,150, and includes the following features:
- Off-Road suspension (without the 2-inch lift)
- Hill Descent Control
- Skid plates
- Heavy-duty air filter
- X31 hard badge
- Opting for the X31 Off-Road Package also includes:
- 2-speed Autotrac transfer case
- 4WD model
- All-Terrain or Mud-Terrain tires
Meanwhile, GMC’s dealer-installed Lift Suspension Upgrade System is priced at $995 for rear-wheel-drive (2WD) vehicles and $1,295 for those with four-wheel-drive (4WD).
Both kits include the following items:
- Front and rear passive monotube dampers
- Front compatibility brackets
- Front jounce bumpers
- Rear leaf spring spacers
- Rear jounce bumper spacers
- Electronic Power Steering calibration
- Front Camera reconfiguration
- Compatible vehicle jack
- Performance emblem
- Instruction sheet
- Replacement fasteners as required
The four-wheel-drive kit costs more because it also includes front half-shafts, which are obviously not required for the rear-wheel-drive vehicle.
Neither of the lift kits can be fitted to vehicles with Adaptive Ride Control (which only applies to the Denali – the only Sierra model to use the suspension system), the Max Trailer Package (RPO code NHT) or the Snow Plow Prep Package (RPO code VYU). Apart from those restrictions, it’s possible to get most GMC Sierra variants very close to AT4 specification at a lower price point (depending on installation costs), and to make two of them – the SLE and SLT – almost identical from a mechanical standpoint.
Those looking to emulate the AT4 treatment to a T will also need to paint the front tow hooks red, while also getting the AT4-specific 18-inch machined aluminum wheels with Dark Grey accents wrapped in the appropriate tires.