AEV Sierra Grande: If a GMC’s HD truck spent a winter off-roading in Australia

Here’s a freezing cold take: The hype around overlanding won’t die anytime soon. Not as long as automakers and the aftermarket keep teaming up to build wild concepts like the Sierra Grande by American Expedition Vehicles.

This seriously re-worked GMC Sierra HD looks like AEV’s answer to the question: “What if you took a workhorse UTV like the Polaris Ranger and super-sized it?”

AEV is responsible for some of our favorite off-roaders, such as the Chevy Colorado ZR2 Bison. As the foundation of its 2023 SEMA (Specialty Equipment Market Association) show build, the company chose a GMC Sierra 2500 HD with a single cab and a long bed, a configuration mostly reserved for full-blown work trucks. From there, the Michigan firm went to town.

An eight-foot aluminum bed replaces the factory unit. This material might seem like an odd choice in the states, but aluminum is a popular move among the overlanding community in Australia; adventurers prefer the utility and configurability of a simple boxed aluminum bed, and are happy to sacrifice payload to get it. A truck whose bed has been swapped with a boxed aluminum one is sometimes referred to as an “Aussie build” in the overlanding world.

Though GMC won’t normally allow you to spec the AT4X upgrades (all the good off-road tech) on a single-cab, long-bed Sierra HD, AEV worked directly with GMC engineers to source and fit most of that package’s components—including the trick MultiMatic DSSV dampers, the steering knuckles, control arms, and the rear suspension layout—to the Sierra Grande.

Up front, AEV cribbed the stamped steel bumper from the Sierra HD AT4X AEV Edition, and fitted it with a prototype brush guard for additional protection to the lights and grille. Speaking of lights, four 7000 series off-road lights have also been added, because you can never have too much illumination while out on the trail. Should you get stuck, there’s a ComeUp 12,500-lb winch integrated into that steel bumper.

To ensure the Sierra Grande’s 6.6-liter Duramax turbodiesel V-8 inhales clean air no matter the watery obstacles it may face, AEV fitted a snorkel of its own design. Underbody armor consists of stamped steel plates for the front end, for the transfer case, and more. Prototype fender flares allow the concept to sit on massive, 40-inch BFGoodrich tires wrapped around AEV Salta XD wheels. Between the massive rubber and the AT4X suspension upgrades, the Sierra Grande concept sits 1.5 inches higher than the Sierra HD you’d see in a showroom.

That added height also makes the aluminum box extra useful. Along with a conventional tailgate, you can drop either side of the bed, whose sides don’t rise nearly as high as those of a traditional truck bed, granting easier access to gear stored closer to the middle of the tray. An integrated vertical tire mount allows you to carry a full-size spare without sacrificing departure angle (as a frame-mounted spare would require). A custom AEV rear bumper further trims the truck for maximum nimbleness.

For good measure, AEV also fitted an ARB onboard air system to help air your tires up or down when transitioning from tarmac to trail. There are chucks on either side of the front of the aluminum bed to which you can hook up an air hose and get yourself road- or trail-ready in no time at all. There’s also a 9,500-lb ComeUp winch at the rear, because why just have one winch when you could have two?

The Sierra Grande is the first time we’ve seen AEV swing at that next level of customization for a GM HD truck—think bed removal and heavy accessorizing. In short, a more extensive job than swapping bumpers, wheels, and tires. That said, AEV is no stranger to kitting out HD pickups; the company has offered a cab-and-chassis and tray-bed version of the Ram HD pickups, which it calls the “Prospector,” for some time. A Prospector cab-and-chassis was the platform for another wild creation unveiled earlier this year through a collaboration with European travel cab maker Bliss Mobil.

The Sierra Grande concept will be on display at SEMA later this week in Las Vegas. While it’s just a concept now, don’t be surprised if news surfaces eventually that AEV will begin a production run of Sierra HD AT4Xs with the “Aussie” treatment like this.

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