2024 GMC Sierra Heavy Duty Goes Hardcore With AT4X And Extreme AEV Edition

• First time the AT4X badge has been used on a Sierra HD
• 18,500-pound max trailering capacity
  
• 1.5-inch suspension lift and Multimatic DSSV dampers
• Locking rear e-differential
• 35-inch Goodyear Territory tires
• AT4X AEV gets stamped steel bumpers and 18-inch Salta wheels.

GMC has introduced the AT4X moniker to the Sierra HD for the first time ever and has also launched an AT4X Extreme AEV Edition too. This is no surprise after introducing ZR2 and ZR2 Bison variants to the Chevy Silverado lineup, the Sierra HD's corporate sibling.

Mechanically, the Sierra HD AT4X follows a familiar recipe, building on the standard Sierra HD AT4 with a 1.5-inch factory lift kit, Multimatic DSSV dampers, and an electronic locking rear differential. For good measure, a set of 35-inch Goodyear Territory tires are equipped, while the suspension is beefed-up with model-specific front control arms (upper and lower) and steering knuckles.

Chunkier skid plates accompany these upgrades, with an aluminum item up front and a steel item for the transfer case.

Thanks to the mechanical upgrades, GMC was able to equip the Sierra HD AT4X with a new Off-Road Mode with custom calibration for the ABS and traction and stability control. A new throttle map and transmission programming setup also alters the truck's behavior on loose surfaces.

Visually, the interior is where you'll see the most changes, with an Obsidian Rush interior theme. Full-grain leather-upholstered seats feature standard massage functionality, while the dash is finished in authentic Vanta Ash wood trim.

Infotainment-wise, a 13.4-inch central infotainment screen complements a 12.3-inch digital instrument cluster and a 15-inch head-up display. A 12-speaker Bose sound system provides audio.

Additional features include the ProGrade Trailering System to unlock a maximum towing capacity of 18,500 lbs (diesel engine only) while making trailering easier than ever with a transparent trailer view, blind-spot monitoring while trailering, and adaptive cruise control for trailering. Up to 14 camera views help you hitch and guide a trailer in any condition.

If the AT4X still isn't enough truck for you, GMC has partnered with American Expedition Vehicles on the Sierra HD AT4X AEV Edition pickup truck.

This derivative features stamped steel bumpers with integrated recovery points, and front winch capability for added peace of mind. The skid plates are even heavier-duty to protect the steering and transfer case running gear. It sets itself apart further with 18-inch Salta wheels and AEV badging.

Inside the cabin, the Obsidian Rush interior gets AEV logos on the front headrests and AEV-branded floor liners.

"The Sierra HD is an ideal foundation when it comes to on-road performance, off-road capability and insane pulling power," says AEV CEO and founder Dave Harriton. "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."

As for power, both versions of the Sierra HD AT4X are powered by a 6.6-liter gasoline V8 as standard (E85 FlexFuel capable), producing 401 horsepower and 464 lb-ft of torque, good for a conventional towing capacity of 16,000 lbs. Optionally, the 6.6-liter Duramax Turbo-Diesel V8 has been revised for 2024 and now has 470 hp and 975 lb-ft with a broader spread of torque.

Both motors are paired with an Allison 10-speed automatic transmission.

Pricing is not yet available and will be published closer to the trucks' arrival at dealerships this fall.

"GMC's AT4X trim, which will be available across the entire GMC truck lineup, offers customers more premium choices when it comes to 'do-it-all' capabilities," said Duncan Aldred, Global Vice President of Buick-GMC. "Each model delivers unique strengths, with the all-new Sierra HD AT4X taking it to the max, giving our customers the most luxurious and most off-road capable HD we've ever offered. AT4X means you can conquer almost any terrain, in complete comfort and with the towing power to bring your recreational toys, gear or camper along for the adventure."