The GMC Sierra HD AT4X Is the Perfect Base for an Overlanding Rig

Following the recent debut of the Chevrolet Silverado HD ZR2 lineup, General Motors is ready to show off GMC’s take on the heavy-duty off-road segment. The brand’s AT4X moniker now expands to the HD lineup for the first time with the all-new Sierra HD AT4X and AT4X AEV Edition models.

Like its Chevrolet-branded sibling, the GMC Sierra AT4X models are based on the brand’s 2500 HD chassis. Customers will have a choice between either a 6.6-liter gasoline or turbo diesel engine. The gasoline engine is rated at 401 hp and 464 lb-ft of torque. The Duramax brings 470 hp and 975 lb-ft of torque, and both engines come exclusively mated to a 10-speed Allison automatic gearbox. All AT4X models include four-wheel drive. The gasoline-powered trucks come rated with a maximum payload capacity of 3291 pounds, whereas the diesels are rated at 3068 pounds. The diesel gets a healthier tow rating of 18,500 pounds however, while the gas truck ranks in at 16,000 pounds.

Off-road upgrades for the GMC Sierra AT4X include unique front control arms and steering knuckles, a 1.5-inch suspension lift, Multimatic DSSV dampers, a steel skid plate for the transfer case, an aluminum front skid plate, and a rear electronic-locking differential. The package also includes a larger set of 35-inch Goodyear Territory tires to help make better use of that improved suspension package. The adjustments help the HD ATX4 achieve 11.6-inches of ground clearance, as well as approach, departure and breakover angles of 31.6-, 25.7- and 21.2-degrees, respectively. Like the HD ZR2, the trucks come bolstered by GM’s Off-Road mode software, which programs ABS, traction control and throttle inputs for maximum control on loose surfaces.

Every GMC Sierra HD AT4X will come equipped with the brand’s premium Obsidian Rush interior package. Highlights include full grain leather seats with front massage functionality, a 12-speaker Bose audio system, as well as genuine Vanta Ash wood used throughout the trim pieces. The trucks also pack a A 13.4-inch-diagonal infotainment screen, which works alongside a 12.3-inch digital cluster to provide all your information. A 15-inch heads-up display is available as an option.