It was a safe bet that after the Chevy Silverado HD ZR2 was announced, a GMC variant would follow. That's what we have here with the 2024 GMC Sierra HD AT4X, a three-quarter-ton hoss that rides on 35-inch Goodyears and Multimatic DSSV dampers. It's mechanically identical to its Bowtie brethren, but it's more upscale for people who don't think the ZR2 is fancy enough. It even has a tougher AEV trim, too.
The Sierra HD AT4X still comes standard with the 6.6-liter gas V8, which makes 401 horsepower and 464 pound-feet of torque. Not shabby, though it's a fair amount less than the 6.6-liter Duramax diesel which makes 470 hp and 975 lb-ft of torque. That's the engine most buyers will spring for, but either way, they're both paired to a 10-speed Allison automatic. An electronic rear locker is standard, but there's no front locker available; GMC insists its Off-Road Mode can alter throttle progression and transmission shifts well enough that you don't need one.
As stout as the powertrain options are, where GM's newest heavy-duty off-road pickup shines is in the suspension department. It sports newly designed upper and lower control arms up front that are specific to the AT4X trim, which is important as it's the only truck in its class with independent front suspension—well, along with the Silverado HD ZR2. Then there are the Multimatic DSSV dampers, which have been used in everything from Indy cars to GM race trucks and now this hard-working behemoth. We could spend this whole blog doing a deep dive on the spool-valve tech, but what's important to know is that they deliver consistently great damping even during repeated use at high temperatures.
The GMC's sturdy frame and suspension allow it to tow 18,500 pounds. It's exclusively available as a 2500 series pickup—there's no one-ton or 3500 series model. Still, that ought to be plenty of towing capacity for anyone who wants to tow their camper to the middle of nowhere and leave it behind for a day of trail driving. All you have to do is make sure the trails are wide enough. The desert is a great place for this, then.
There's a steel skid plate to keep the transfer case safe from rocks, while the front skid plate is made of aluminum unless you spring for the AEV Edition. That not only nets you all-steel underbody protection but also stamped steel bumpers with the capability to accept a winch up front. A set of 18-inch Salta wheels tie the look together, along with a handful of AEV badges throughout.
The real reason you'd buy the GMC over the Chevy is its interior. The truck's cab, which is designed in what the automaker calls an Obsidian Rush scheme, has massaging leather seats that keep you loose in even the tensest driving situations. I think I'd probably get distracted trying to maneuver through a tricky rock garden while something digs into my lower back, but maybe that's just me. A total of 14 available camera views should make it easier to see what's in front of, behind, and below as they cast real-time footage to the 13.4-inch digital touchscreen. There's also a 12.3-inch digital gauge cluster and a 15-inch heads-up display, so there's no shortage of information being fed to the driver. Finally, Vanta Ash wood accents and a 12-speaker Bose Premium Series sound system reinforce that this is a great place to spend a day.
All that tech is backed up by a suite of safety features like transparent trailer view and available trailer side blind zone alert as well as adaptive cruise control with towing capability. It's meant to make the trailering experience as painless as possible, which is something we all ought to appreciate, no matter how seasoned you are at pulling a gooseneck or what have you.
GMC hasn't said how much this rig will cost, so expect that to be announced when it gets closer to production in the fall of 2023. You can throw out some ridiculous number and probably get pretty close as it's sure to be pricey. This really is a new breed of four-wheeler.
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