The 2024 GMC Sierra HD AT4X AEV Climbs, and Moves, Mountains

The GMC Sierra HD AT4X AEV is as long as a line of 20 people. It’s strong enough to relocate up to 18,500 pounds of earth or pull the enormity of a single EarthRoamer. It’s the heaviest Sierra HD sold, with a crushing 8605-pound claimed curb weight. With its mirrors extended, it’s wider than a full-size school bus, and if you thought the regular Sierra HD was tall, the AEV version reaches roughly two inches further into the sky. While its dimensions illustrate how cartoonishly huge the biggest pickups have become, the AT4X AEV also gives GMC’s mightiest pickup truck serious capability.

Taking the already off-road-equipped Sierra HD AT4X to the next level, the AT4X AEV gets the American Expedition Vehicle treatment. That includes AEV stitched headrests and as many badges as the local police precinct, but there’s also useful stuff, such as the hot-stamped steel front and rear bumpers.

The Sierra HD AT4X AEV comes exclusively as a 2500HD crew cab with the standard 6-foot 9-inch bed and four-wheel drive. Both the 401-hp 6.6-liter V-8 gasser with 464 pound-feet of torque and the preferred 470-hp turbocharged 6.6-liter V-8 Duramax diesel powerplant with 975 pound-feet of torque are offered. A 10-speed automatic transmission bolts to either, but the final drive ratio for the gas engines is 3.73:1 while diesels get 3.42 gearing. Both powertrains slurp from a 36.0-gallon fuel tank.

The 35-inch Goodyear Wrangler Territory MTs wrapping AEV’s exclusive 18-inch aluminum wheels add to this package’s rugged premise. Don’t let the big-truck guys in on a little secret: The mid-size Canyon AT4X AEV is on the same overall diameter tires, just mounted on smaller 17-inch wheels instead. Our time with the AT4X AEV was completely off-road, so we can’t report on their highway-speed noise level.

The AEV has the same 1.5-inch suspension lift as the HD AT4X and includes its Multimatic DSSV spool-valve dampers, which are unlike anything from other off-road-themed heavy-duty pickups from Ram and Ford. The dampers create a shockingly smooth ride as they soak up the ohs and ouches of uneven off-road terrain.

On a trail near Big Sky, Montana, the HD AT4X AEV met a 28.0-degree descent down a slippery rock section of Yellowstone country. It dug its claws in like a grizzly bear, calmly lowering itself to the base of the hill as if it had grown up eating berries. Like the Chevy Silverado HD ZR2 Bison the GMC is based on, the AT4X AEV also uses an independent front suspension. The same steel used to make the AEV bumpers is also employed on the belly of this whale to protect its transfer case, while the skid plate under its nose is aluminum. There are also massive tow hooks, should things go massively wrong.

According to GMC, the chromed-up Denali is the sales leader among Sierra HD pickups. GMC says its expects 40 percent of AT4X trucks to get the AEV treatment. We’d argue that as ridiculously Herculean as these trucks are, the useful equipment added for AT4X and AT4X AEV is more practical than the Denali’s shiny grille.

The HD AT4X AEV still has all the stuff less aggressive trims offer. The ergonomically comfy radio tune and volume controls behind the steering wheel work via fingertip. GM’s rearview mirror camera turns the dust you’ve kicked up behind you into a high-definition motion picture film. Instead of the steel rock sliders found in AT4X AEV versions of the Sierra 1500 and the Canyon, the HD model still has a powered step rail. And it’s a good thing, because with 11.8 inches of ground clearance, you might otherwise need cowboy stilettos to climb aboard.

Like purchasing a spread in Montana, obtaining this outsized truck requires herding Benjamins by the barnful. The 2024 Sierra 2500HD AT4X AEV is $94,290. That’s $9495 extra on top of the AT4X, and it dwarfs the $76,195 needed to lasso a Denali or the $72,560 Ram asks for an HD Power Wagon. Compared to the Chevy version, which starts at $82,085 for the ZR2 Bison with similar AEV-equipped body armor, the GMC does seem like a bragging chip rather than a bargain. Oh, and tack on another $9490 for the Duramax diesel. However, if there’s one thing more ridiculous than a $94K heavy-duty pickup clambering through the woods, it’s gotta be a $76K truck that’s too afraid to.

Source: Reviews - aranddriver.com