2024 GMC Sierra HD AT4X Photos, engines & full specs

GMC has completed its off-road-oriented lineup of trucks with the introduction of the 2024 Sierra HD AT4X and its even more rugged sibling, the HD AT4X AEV.

Both versions were launched simultaneously in spring 2023, throwing the gauntlet toward what RAM and Ford already had on their offers. But GMC waited a little bit more, and the result was astonishing. The big rig was able to pull anything with wheels on it, and it could also provide comfort and a "get out of my way" appearance.

The GMC Sierra 2500 HD was already a big truck on the road, but it was mainly built for construction sites or to pull a heavy load on a trailer behind it. But the AT4X version came with an enhanced look that boasted a huge black grille up front, a black bumper, and two exposed red towing hooks. The headlights were carried over from its less-hardcore off-road sibling, the 2500 HD. From its side, the high ground clearance was noticeable, and so were the 35" MT tires mounted on the 18" alloy wheels. On its sides, to ease reaching out inside the bed, the automaker installed side steps on the rear quarter panels.

But all that rugged exterior look was hiding a wide and spacious cabin for five people. Boasting massaging front seats, a full-grain leather-wrapped interior, and a Bose sound system, it was the truck aimed for those ready to travel long distances toward their next camping location. The dashboard was fitted with a 13.4" touchscreen for the infotainment system and a 12.3" instrument panel in front of the driver.

Powering this behemoth truck was either a 6.6-liter gasoline engine or a same-displacement Duramax turbo-diesel powerplant.