The GMC Sierra HD AT4X AEV is a colossal beast, measuring as long as a line of 20 people. It possesses the Herculean strength to move a staggering 18,500 pounds of earth or tow the immense weight of an EarthRoamer. It is, without a doubt, the heaviest among Sierra HD models, boasting a claimed curb weight of 8605 pounds.
With its mirrors fully extended, it stretches wider than a typical school bus and even surpasses the height of the standard Sierra HD by about two inches. These dimensions underscore the colossal nature of contemporary pickups, but the AT4X AEV is not just about size; it also delivers formidable capability for GMC’s most potent truck.
Taking the already off-road-ready Sierra HD AT4X to the next level, the AT4X AEV receives the American Expedition Vehicle treatment, complete with AEV-stitched headrests and a multitude of badges. However, it also incorporates practical features, such as hot-stamped steel front and rear bumpers.
The Sierra HD AT4X AEV is exclusively available as a 2500HD crew cab with a standard 6-foot 9-inch bed and four-wheel drive. It offers a choice between a 401-horsepower 6.6-liter V-8 gasoline engine with 464 pound-feet of torque and a preferred 470-horsepower turbocharged 6.6-liter V-8 Duramax diesel engine with a remarkable 975 pound-feet of torque.
Both powertrains are mated to a 10-speed automatic transmission, but the gas engines have a final drive ratio of 3.73:1, while the diesel variants get 3.42 gearing. Both engines draw fuel from a substantial 36.0-gallon tank.
The package includes 35-inch Goodyear Wrangler Territory MT tires wrapped around exclusive 18-inch aluminum wheels, reinforcing its rugged capabilities. However, we can’t comment on their noise levels at highway speeds, as our experience with the AT4X AEV was entirely off-road.
The AT4X AEV shares the same 1.5-inch suspension lift as the HD AT4X and incorporates Multimatic DSSV spool-valve dampers, setting it apart from other off-road-oriented heavy-duty pickups from Ram and Ford. These dampers deliver an impressively smooth ride, absorbing the bumps and imperfections of uneven off-road terrain.
During a trail adventure near Big Sky, Montana, the HD AT4X AEV effortlessly tackled a 28.0-degree descent down a slippery rock section of Yellowstone country, displaying its impressive off-road prowess. Like the Chevy Silverado HD ZR2 Bison it’s based on, the AT4X AEV also boasts an independent front suspension.
It utilizes the same steel used for the AEV bumpers to shield its transfer case, while the skid plate under its front is constructed from aluminum. Massive tow hooks are included, just in case things take a massive turn for the worse.
According to GMC, the chromed-up Denali remains the top-selling variant among Sierra HD pickups, but the company anticipates that 40 percent of AT4X trucks will receive the AEV treatment. It could be argued that as imposing as these trucks are, the practical enhancements provided in the AT4X and AT4X AEV models outweigh the allure of the Denali’s shiny grille.
The HD AT4X AEV retains all the features found in less aggressive trims. The ergonomically designed radio controls behind the steering wheel are easy to operate with just a fingertip. GMC’s rearview mirror camera turns the dust raised by the truck into a high-definition motion picture.
Instead of the steel rock sliders featured in AT4X AEV versions of the Sierra 1500 and the Canyon, the HD model is equipped with a powered step rail. This proves essential, given the truck’s impressive 11.8 inches of ground clearance.
Owning this colossal truck is no small investment, requiring a substantial outlay. The 2024 Sierra 2500HD AT4X AEV starts at $94,290, which is a substantial $9,495 premium over the AT4X model. This price significantly overshadows the $76,195 needed for a Denali or the $72,560 required for an HD Power Wagon from Ram.
In comparison to the Chevrolet version, which starts at $82,085 for the ZR2 Bison with similar AEV-equipped body armor, the GMC may be viewed as more of a status symbol than a budget-friendly choice. Additionally, adding the Duramax diesel option will set you back another $9,490. Nevertheless, if there’s anything more absurd than a $94,000 heavy-duty pickup truck navigating the wilderness, it’s a $76,000 truck that’s too timid to do the same.