The GMC Sierra AT4 made an impact in the off-road market when it was released in 2019, but the all-new 2022 Sierra AT4X takes that to a whole new level. I had the chance to get behind the wheel of the truck and not only test it on-road, but I also was able to take it out to Anza-Borrego in Southern California to put it through the paces off-road.
Before I get into the off-road capability of the truck, I want to reiterate that the main goal of the GMC team was to create a vehicle that could perform at a high level off-road but not compromise on the on-road comfort. The numbers do not lie, and only around 19 percent of truck owners are truly going to off-road in their pickup.
The AT4X comes standard with the 6.2-liter V-8 engine paired with a 10-speed automatic transmission putting out 420 horsepower and 460 pound-feet of torque, with a payload capacity of 1,420 pounds and an 8,900-pound towing capacity. The drivetrain also features a two-speed Autotrac transfer case and a 3.23 axle ratio.
The MultimaticTM DSSV spool-valve dampers are the true star of the show, and the tuning done on them is able to create a smooth ride on-road while being able to handle the harsh off-road terrain. To help in sticky situations, the AT4X features a front and rear e-locking differential.
Being a 2022 model, the AT4X did see the same refresh that the GMC Sierra lineup underwent, which featured exterior styling changes, but it also received interior improvements of the standard 15-inch diagonal head-up display, 12.3-inch diagonal digital instrument cluster, and 13.4-inch diagonal infotainment screen.
Heated and ventilated 16-way power front seats with massage and the Obsidian Rush interior featuring a full-grain leather seating with technical grain leather accents and authentic Vanta ash wood all added to the luxury feel of the pickup. The 12-speaker Bose stereo with Centerpoint surround sound kept the music loud and crisp on- and off-road.
I had plenty of time to check out the interior and get a feel for the truck as I made the two-hour drive from the Southern California coast to the desert. I hit open roads and some curvy mountain roads, and the seats in the AT4X kept us firmly planted and not sliding everywhere.
On the curvy roads, I did notice that the truck felt planted. It did not feel that it was too big to be on a twisty mountain road or feel like there was a ton of body roll.
Driving the AT4X, you could tell that it was ready for more; the drive on the pavement was a tease because I knew that the fun in the dirt would happen shortly.
The Road to Diablo Drop Off
A quick lunch and tire air-down got the GMC Sierra AT4X ready for its impending off-road adventure to Diablo Drop Off. The AT4X is equipped with 18-inch wheels wrapped in LT275/65R18 (32-inch) Goodyear Wrangler Duratracs.
I asked one of the GMC engineers on hand why they didn’t go with a larger tire like other manufacturers have done recently, and it came down to the team not wanting to ruin the look of the truck. The AT4 has done very well for GMC, and they did not want to change that on the AT4X to continue that success.
The AT4X is built for off-road with a 25.5-degree approach angle, 23-degree departure angle, 9.84-inch front-suspension travel, 10.62-inch rear-suspension travel, and 11.1 inches of ground clearance. I would be putting all of the angles to the test with the impending off-road testing.
I headed out to Diablo Drop Off through some wide-open washes where I hit speeds between 50 and 60 miles per hour, all while enjoying a smooth ride. The Multimatic DSSV shocks handled the washboard road and kept the truck planted on the dirt.
If you have been on a washboard road before, you know that it can unsettle a truck and start to pitch the truck side to side. The AT4X did not do that; I did not feel at any time that I needed to slow down or correct how the truck was tracking.
On the pavement, the all-new 15-inch head-up display was able to display a ton of features, not just vehicle speed. When it came to off-road driving, I actually found that the head-up display was more of a nuisance.
The display could be adjusted or turned off, but I found myself driving without it. The display was a distraction and actually disrupted my view of the trail; coupled with the dust from the truck in front of me, it was harder to see particular lines in the dirt.
I hit some tight sections on the trail and was able to use the camera integrated into the grille of the AT4X. It made getting a full-size truck through some tight areas much easier.
Upon arriving at Diablo Drop Off, the views were incredible; I could see the Anza-Borrego desert for miles in all directions, but I also saw a steep decline that I would be taking the AT4X down and back up. This was a steep 15-degree decline with large, alternating ruts that would be testing everything on the truck.
The AT4X features a two-speed transfer case with selectable modes, including Terrain Mode, which allowed for one-pedal driving. One other mode that I used for the entire drive-out was Off-Road Mode, which gives the driver more control of the truck and the ability to get more wheel spin when needed.
A larger steel transfer case skid plate and the installed performance rocker protection, which does not come standard on the AT4X, could be heard scraping down the hill. This was a no-joke trail that we all had the chance to experience.
When it was my turn to head down Diablo Drop Off, I put the truck into manual mode, in gear L1 with rear locker engaged, and used Terrain Mode. I had played with Terrain Mode earlier and had an idea how much gas I had to give the truck going down the hill.
The truck went down the hill rocking back and forth through the ruts, all while scraping each rocker guard. Having the truck in Terrain Mode made the descent more comfortable because I did not need to worry about feathering the gas, giving the truck too much gas, or having to drive with two feet.
Once I got through the ruts, it was a soft sandy decline to the bottom of the hill before I turned around, engaged the front locker, and climbed back up the hill, taking an alternate route up another sandy, rutted-out section.
With all the AT4X’s going through the drop-off section, I turned around to get aired up and hit the road back. I was impressed during the entire drive, especially with how well the AT4X did in the climbing sections. The biggest takeaway was how well the truck drove on the road but then was able to go extreme off-roading and still drive back after.
Regardless of what I put the 2022 GMC Sierra AT4X through on my full day with it, it handled everything smoothly. There wasn’t a time when I felt that the truck needed more or that it was lacking. The $77,395 starting price is steep, but when you look at everything you get, it’s hard to argue the performance on- and off-road.
