GMC is introducing the Sierra HD AT4X with the intent that there is no heavy-duty task too challenging or overlanding setup too big.

Sierra HD AT4X Interior
Sierra HD AT4X Interior

Introduced on the heels of the Silverado HD ZR2, the Sierra HD AT4X carries an identical complement of upgrades, tricks, and capabilities. What are they exactly? Let’s take a look!

Interested in connecting with other Sierra HD owners and enthusiasts?
Visit the GM-Trucks.com Forum
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If the Chevrolet Silverado is more your style- the Silverado HD ZR2 is worth a look!

Sierra HD AT4X AEV
Sierra HD AT4X AEV

What is the Sierra HD AT4X?

  • Standard 6.6L Gasoline Engine
  • Available 18,500 lb towing capacity
  • Factory 1.5-inch lift
  • Multimatic DSSV Dampers / Shocks
  • 35-inch Goodyear Territory Tires
  • E-Locking Rear Differential
  • Specific upper and lower control arms to fit the factory lift
  • Steel transfer case skip plate
  • Aluminum front skid-plate
  • Unique “Obsidian Rush” interior color scheme with premium features like massaging front seats and full-grain leather seating
  • Standard “Off-Road Mode” which calibrates the anti-lock brakes, stability control, and traction control to keep the vehicle planted off-road.
  • Included 14-camera-view off-road vision system with transparent trailer
  • 13.4-inch diagonal infotainment screen with 12.3-inch digital gauge cluster
  • 15-inch heads up display
  • 12 speaker Bose Premium series audio system with Centerpoint
  • Optional 6.6L Duramax Diesel Engine w/470 horsepower and 975 lb-ft of torque
  • Both engines mated with 10-speed Allison automatic transmission
Sierra HD AT4X Multimatic DSSV Dampers
Sierra HD AT4X Multimatic DSSV Dampers

Sierra HD AT4X AEV Edition

If all of those features were not enough to satisfy- the Sierra HD AT4X AEV Edition is here to quench your overlanding thirst.

The AEV Edition builds upon the HD AT4X with additional features. Those include stamped steel bumpers with winch and recovery provisions. An even more robust skid-plate system that additionally protects the steering system and transfer case. There’s also AEV-specific 18-inch Salta wheels for extra durability off-road.

“The Sierra HD is an ideal foundation when it comes to on-road performance, off-road capability and insane pulling power,” said AEV CEO and founder Dave Harriton. “As with the Sierra 1500 before it, we took AEV’s signature performance-driven approach and dedication to detail to elevate the aspects that off-road customers want and demand in their heavy-duty truck. The result is an awesome truck with capability and confidence in all the right spots.”

Sierra HD AT4X AEV
Sierra HD AT4X AEV

Why is GMC building an HD Overlanding Rig?

As overlanding has increased in popularity, more extensive and significant setups have permeated the community. You’ve probably noticed that slide-in-bed campers can get quite large. An HD truck with off-road capability is a perfect starting point for someone who wants to bring their truck off the beaten path for weeks at a time and allows customers to load up even more of their stuff for the trip.

Sierra HD AT4X Interior
Sierra HD AT4X Interior

2024 GMC SIERRA AT4X & AT4X AEV EDITION SPECIFICATIONS

CONFIGURATION

2500HD Crew Cab Standard Bed (4WD)

 

ENGINES

Type: 6.6L V-8 gasoline or E85 FlexFuel
Bore & Stroke (in. / mm): 4.06 x 3.86 / 103.25 x 98
Block Material: Cast iron with nodular iron main caps
Cylinder Head Material: Cast aluminum
Compression Ratio: 10.8:1
Valvetrain: Overhead-valve, two valves per cylinder, variable valve timing
Fuel Delivery: Direct fuel injection
Horsepower (hp / kW @ rpm): 401 / 299 @ 5200 (SAE certified – gasoline)
Torque (lb.-ft. / Nm @ rpm): 464 / 629 @ 4000 (SAE certified – gasoline)
Type: Duramax 6.6L V-8 Turbo-Diesel
Bore & Stroke (in. / mm): 4.05 x 3.89 / 103 x 99
Block Material: Cast iron
Cylinder Head Material: Cast aluminum
Compression Ratio: 16.0:1
Valvetrain: Overhead-valve, four valves per cylinder
Fuel Delivery: Common-rail direct fuel injection
Horsepower (hp / kW @ rpm): 470 / 350 @ 2800 (per SAE J1349)
Torque (lb.-ft. / Nm @ rpm): 975 / 1322 @ 1600 (per SAE J1349)

 

TRANSMISSION & AXLE

Type: Allison® 10L1000 10-speed automatic
Gear Ratios (:1):  
First 4.54
Second 2.87
Third 2.06
Fourth 1.72
Fifth 1.48
Sixth 1.26
Seventh 1.00
Eighth 0.85
Ninth 0.69
Tenth 0.63
Reverse 4.54
Final Drive Ratio: 3.73 (6.6L gas)
3.42 (6.6L diesel)

 

CHASSIS & SUSPENSION

Front Suspension: Independent front suspension with torsion bars
Rear Suspension: Semi-elliptic, two-stage, multi-lead springs
Steering Type: Hydraulic power-assisted recirculating ball
Brake Type: Hydraulic power-assisted Hydroboost brake booster, four-wheel disc brakes with ABS and Stabilitrak electronic stability assist
Brake Rotor Size (in. / mm): Front: 14 x 1.6 / 355 x 40
Rear: 14.1 x 1.3 / 360 x 34
Wheel Size: 18 x 9-in. aluminum
Tire Size: LT305/70R18 MT

 

FUEL TANK CAPACITY (approx.)

Fuel Tank (gal. / L): 36 / 136 (gas and diesel)

 

EXTERIOR DIMENSIONS

Wheelbase (in. / mm): 159.1 / 4042
Overall Length (in. / mm): 250.7 / 6369 (AT4X)
252 / 6401 (AT4X AEV Edition)
Overall Width (in. / mm): 81.9 / 2079 (without mirrors)
105.1 / 2670 (with mirrors extended)
Overall Height (in. / mm): 82.6 / 2100
Front Track (in. / mm): 69.3 / 1762
Rear Track (in. / mm): 70.0 / 1760
Ground Clearance (in. / mm): 11.6 / 295 (AT4X)
11.7 / 299 (AT4X AEV Edition)
Approach Angle (deg.): 31.6 (AT4X)
29.8 (AT4X AEV Edition)
Departure Angle (deg.): 25.7 (AT4X & AT4X AEV Edition)
Breakover Angle (deg.): 21.2 (AT4X)
22.6 (AT4X AEV Edition)

 

INTERIOR DIMENSIONS

Headroom (in. / mm): 43.03 / 1093 (front)
40.12 / 1019 (rear)
Legroom (in. / mm): 44.53 / 1131 (front)
43.4 / 1102 (rear)
Shoulder Room (in. / mm): 66.02 / 1677 (front)
65.3 / 1659 (rear)
Hip Room (in. / mm): 61.18 / 1554 (front)
60.24 / 1530 (rear)

 

CURB WEIGHT, GVWR & PAYLOAD1

Base Curb Weight (lb. / kg): 7516 / 3409 – AT4X gas
8237 / 3736 – AT4X diesel
7894 / 3581 – AT4X AEV Edition gas
8605 / 3903 – AT4X AEV Edition diesel
GVWR (lb. / kg): 10850 / 4921 – AT4X gas
11350 / 5148 – AT4X diesel
10850 / 4921 – AT4X AEV Edition gas
11350 / 5148 – AT4X AEV Edition diesel
Payload1 (lb. / kg): 3291 / 1493 – AT4X gas
3068 / 1392 – AT4X diesel
2912 / 1321 – AT4X AEV Edition gas
2701 / 1225 – AT4X AEV Edition diesel

1For comparison purposes only. See the owner’s manual and the label on the vehicle door jamb for the carrying capacity of a specific vehicle.

MAX TRAILERING1

Conventional (lb. / kg): 16000 / 7257 – AT4X gas
18500 / 8391 – AT4X diesel
16000 / 7257 – AT4X AEV Edition gas
18400 / 8346 – AT4X AEV Edition diesel
Fifth-Wheel/Gooseneck
(lb. / kg):
18000 / 8165 – AT4X gas
17300 / 7847 – AT4X diesel
16200 / 7348 – AT4X AEV Edition gas
14800 / 6713 – AT4X AEV Edition diesel

1Before you buy a vehicle or use it for trailering, carefully review the Trailering section of the Owner’s Manual.

NOTE: All towing capabilities measured using SAE J2807 metrics.