GMC was considered a pioneer in the luxury pickup space when it launched the first Sierra Denali model more than 20 years ago. But while GMC has certainly led the industry in premium trucks, when it comes to playing in the dirt, the brand hasn’t been as progressive.
GMC has spent much of the past decade watching from the sidelines as other manufacturers unleash some fairly incredible off-road packages. The Ford Raptor and Ram TRX come to mind, and while those two are still in a class of their own, GMC finally launched the more capable Sierra AT4 in 2018. With a two-inch lift, Rancho shocks and tall, aggressive Goodyear Duratrac tires, four-wheeling enthusiasts finally began to notice GMC.
But for 2022, the brand has decided to up the ante even further. Meet the Sierra AT4X, the mechanical twin to Chevrolet’s new Silverado ZR2. The X has quite a bit more trail equipment than the normal AT4 and that helps to boost its capability. But this plush truck is also a bit more expensive than the competition. So is the AT4X enough truck at the right price to turn the heads of the hardcore 4X4 enthusiasts? I spent the day getting a little dusty in southern California’s Anza Borrego desert to find out.
2022 GMC Sierra AT4X Specs
- Base price: $77,395
- Powertrain: 6.2-liter V8| 10-speed automatic | four-wheel drive
- Horsepower: 420 @ 5,600 rpm
- Torque: 460 lb-ft @ 4,100 rpm
- Wheelbase: 147.5 inches
- Dimensions (length | width | height): 232.9 inches | 81.2 inches | 78.4 inches
- Seating capacity: 5
- Towing capacity: 8,900 pounds
- Off-road angles: 25.5 degrees approach, 23 degrees departure, 22.7 degrees breakover
- Ground clearance (max): 11.1 inches
- Curb weight: 5,640 pounds
- Payload: 1,420 pounds
- Fuel economy: 15 mpg city | 19 highway (est.)
- Quick take: A powerful, capable and comfortable 4X4 for those that don’t shy away from a premium price tag.
- Score: 7.5/10
Now let’s get this out of the way right now. The AT4X isn’t a true competitor to the top dog off-roaders from Ford and Ram, like the legendary Raptor and the fire-breathing Ram TRX. The AT4X is not a truck designed to emulate a Baja-style Prerunner with gobs of wheel travel and it doesn’t wear humongous tires, either. Nope, the AT4X is a better slow-speed crawler than it is a high-speed desert machine. It comes closest to emulating the F-150 Tremor in terms of its off-road skillset.
The X is really an evolution of the AT4. First, the X maintains the two-inch lift of the regular AT4. However, the suspension uses unique springs that allow about two inches more wheel travel in the front and an extra inch in the rear. That adds up to 9.84-inches of travel up front and 10.62 inches in the rear—decent numbers, to be sure. And the more wheel travel (total compression and rebound movement of the suspension) a truck has, the better it can keep the tires in contact with the terrain and maintain traction. Engineers developed, upsized and improved a version of the Multimatic DSSV spool-valve dampers for the X similar to the ones Chevy used in the Colorado ZR2. Instead of fitting massively larger rubber, the X uses the same 275/65R18 Goodyear Wrangler Duratrac tires as the AT4 and allow for 11.1-inches under the front skid plate.
However, off-road proficiency requires more than just suspension and tires. GMC has used the same G80 “automatic locking differential” in the rear axle of their trucks for years. The unit uses a flywheel mechanism and a clutch system to lock. The trouble is, it takes quite a bit of wheel slip to get the diff to eventually lock up. And that makes it very difficult to drive smoothly on tricky trails. But on the new AT4X, that diff is history. And it’s about time. In its place is a proper electronic locking differential. Just press a button on the dash and the rear axle instantly locks. But here’s the game-changer: GMC added one upfront, too. No other light-duty full-size pickup (besides the Silverado ZR2) has a locking front differential. The Raptor and F-150 Tremor both use a Torsen limited-slip differential in the front axle. A limited-slip certainly helps, but a true locker takes traction to another level for slow-speed four-wheeling by providing equal torque to each wheel, all the time.
Climb up into the cab of the AT4X and you’ll notice the interior is fresh for 2022. It’s similar to the Denali Ultimate I spent time in a day earlier but trimmed in less swanky materials with darker, less welcoming color tones. But much of the functionality is shared with that truck. That means you’ll have two giant screens, a 12.3-inch instrument cluster and a 13.4-inch infotainment screen, with excellent usability.
GMC’s cluster is highly reconfigurable so you can change the layout radically from a minimalist look to one that displays nearly every gauge you could ever want. And some of that information, including hill and side-slope angles when driving off-road are projected right onto the heads-up display. The interior is loaded with luxury touches like massaging seats, a microsuede headliner and a handsome console shifter. And I really like that there are plenty of hard switches to handle many of the truck’s functions as well as dual glove boxes. Although the upper one is fairly tight, barely fitting a couple of water bottles.
Unfortunately, the 4WD switch is treated as an afterthought. GMC installs this tiny rotary knob and button combination down by the driver’s left knee. And that makes it difficult to use. The AT4X is a truck designed for off-roading, so the 4WD controls should be easy to see and easy to reach—not hiding next to the headlamp switch.
The ATX4 comes standard with GM’s robust 6.2-liter V8. And in this truck, it’s a total blast. There’s plenty of power on the street and the 10-speed automatic works very well to keep the truck in the right gear. This is a relatively tall truck wearing thick rubber, so it feels a little less nimble than the Denali. Still, compared to the wide-track dirt machines like the Raptor and TRX, the AT4X is a breeze to drive on tighter roads and is easy to park. The AT4 rides with a smoothness I wasn’t expecting. And while those Goodyear tires are a bit noisy compared to other all-terrain tires, this is one comfy truck.
And that’s true off-road too. On washboard-style dirt roads, the suspension really soaked up the abuse. The cab was fairly quiet and didn’t quiver as some trucks do on rough roads. Even better, the rear axle stayed in contact with the road and didn’t skip and skitter around. Impressive.
After lunch in the desert, the GMC team aired our tires down to 25 psi for enhanced traction, flotation and comfort. As I headed deeper into the desert with the GMC convoy, the AT4X really came into its own. In the 4WD high range, the truck had no trouble powering through a silt bed and absorbing the impacts from abrupt ledges and drop-offs. Of course, this isn’t what you’d feel in a Ram TRX or Ford Raptor, but it was still comfortable and I never felt the suspension bottom out.
The 4X4s that play in the AT4X’s sandbox all offer a suite of drive modes with names like Rock Crawl, Baja or Mud and Sand. These names clearly communicate each mode’s mission. GMC has a different strategy. The AT4X has two modes: Off-road and Terrain. And unless someone tells you what each one is for, it’s a little confusing. Off-road mode is the one you choose if you want the least assistance from the truck. It’s the one that lets you slide the truck around without too much electronic intervention.
Terrain mode is designed to help relatively inexperienced drivers maintain control. Select this one if you want an automatic one-pedal drive mode while negotiating off-road obstacles. And the parameters of these modes change somewhat when you engage low range. Both work well for what they are designed for, but my preference would be to have more clarity—several modes that correspond to specific off-road conditions.
After about an hour of cruising through the dry washes and sandy canyons, our group arrived at a more technical mogul section. Still in the high range, I crept through the humps and bumps with the rear axle locked and could really feel the suspension working. When I got out of my truck and watched the others go through, I could see the GMC’s tires compress deeply into the fenders and droop down into the holes. This is a truck suspension that works well for slow-speed off-roading.
Later, our convoy arrived at the most technical section, an area named “Devil’s Drop Off." The tire pressures were further dropped to 15 psi and I engaged low range. This is a steep off-camber descent with deep ruts and gullies along the whole route. It really showcases a vehicle’s clearance as well as a suspension’s articulation as tires at both ends of the truck move all the way inside fenders at maximum up-travel and then arc downward to reach for the ground.
These are big bumps and at times, one rear tire would hang in the air for a moment when the terrain dropped away, and then land and repeat the cycle. Those moguls are deep, so as our Sierra traversed each one, you could hear and feel the optional rocker protectors (definitely buy them if you plan to take this truck off-road) touch down onto the sandy soil and scrape along. At the bottom, I spun the truck around and prepared for the ascent back up to the plateau where I started. The path up was a bit less challenging but I still locked both axles this time. And with just a gentle prod of the throttle, the GMC was able to walk its way up with little drama.
There wasn’t much that day that posed a true challenge to these GMCs. I’d like to get one on my home turf to see what it can do. It’s clearly a great package for slow-speed trails. I could imagine this truck, with its payload of 1,420 pounds and tow capacity of 8,900 lbs. would be an excellent pickup for overlanding. It’s certainly one that will provide loads of fun on and off the road.
That said, at over $77,000 the AT4X is expensive even with the generous list of standard equipment. Its mechanical twin, the Chevy Silverado ZR2, has a base price that comes in about $7,000 cheaper. An F-150 Tremor is an even better deal, starting at just under $55,000. Select just about every option Ford offers and you’ll see the sticker close in on $69,000. Heck, for the price of an AT4X you could have a Ford Raptor.
The AT4X is a great truck with some valuable off-road tech. And I dig the classy, understated and upscale design. But I’m not convinced that the GMC badge on the front is worth such a significant price premium.
Ben Stewart resides in Southern California and has been an automotive journalist for nearly 30 years. He specializes in reviewing cars, trucks, and SUVs.
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