The GMC Sierra 1500 lineup has been updated for mid-2022 with fresh styling and a more refined interior, but that's not the exciting news.

The full-size pickup is now available in a crew cab, short bed AT4X model that promisees the most extreme off-road capability of any Sierra 1500. It's a mechanical twin to the 2022 Chevrolet Silverado ZR2 and features all the same technical upgrades.

Key among them is a high performance suspension system designed to handle everything from cruising down the boulevard to rock crawling and high speed off-road driving.

It offers increased wheel travel and uses a special type of shock absorber built by race car builder Multimatic that was originally developed for IndyCars and Formula One cars and was used on the most recent Chevrolet Camaro Z28, but has since been adopted for off-road use and is also available in the midsize Chevrolet Colorado ZR2.

GMC Sierra AT4x

The GMC Sierra AT4X has the most off-road capability of any truck in the lineup. (Fox News Autos)

The shocks use a series of spool valves to precisely control the flow of the fluid within them. They're tuned to give the shocks progressive damping that keeps them soft on rough roads at slow speeds, but stiffens them up when subjected to quick, jarring impacts to keep the body under control in quick turns and the suspension from bottoming out over big bumps.

Multimatic shocks

The exterior of Chevrolet’s ZR2 Multimatic DSSV Position Sensitive Spool Valve Dampers. In all views, the damper with the coil spring is for the truck front, and the one with the protective sleeve is for the truck rear.

The ATX4 comes standard with the Sierra's 420 hp 6.2-liter V8, 10-speed automatic transmission, a two-speed 4x4 system with a full-time all-wheel-drive setting, front and rear locking differentials for maximizing traction and unique 18-inch wheels with mud-terrain tires.

GMC Sierra AT4X rear

The AT4X features a 2-inch body lift and 11.1 inches of ground clearance. (GMC)

It also has a two-inch body lift compared to other Sierras, 11.1 inches of ground clearance and improved underbody protection that includes a larger skid plate for the transfer case.

GMC Sierra dash

The 2022 GMC Sierra lineup has been updated with a new interior with a widescreen infotainment system display. (GMC)

The cabin is dressed to the nines to help justify the AT4X's starting price of $77,395, and features leather upholstery, ash wood trim, climate-controlled massaging front seats, and a 360-degree camera system for the new 13.4-inch touchscreen infotainment system display that is the centerpiece of the new interior look.

GMC Sierra seats

The GMC Sierra AT4X is equipped with massaging front seats. (GMC)

Out back, the AT4X has GMC's Multi-Pro tailgate, which can be opened six different ways to create various storage solutions, a desk or a step. The only major option available on the very loaded truck is a $1,970 technology package that adds a video rearview mirror, head-up display adaptive cruise control and a power adjustable steering column.

GMC Sierra step

GMC's Multi-Pro tailgate can be opened in a variety of configurations. (GMC)

Its payload rating is 1,420 pounds and it can tow up to 8,900 pounds.

The AT4X's closest competitor is the Ford F-150 Raptor, which has a wider body and an even more aggressive suspension, although its 450 hp turbocharged 3.5-liter V6 doesn't add a lot more punch. A more powerful Raptor R is coming later this year, but the Ram 1500 TRX is the current king of the hill with its 702 horsepower supercharged V8.

REVIEW: THE FORD F-150 RAPTOR IS AN ANIMAL

With some irony, the AT4X's equipment provides it with a better on road ride than some of the more street smart Sierras, although its lifted stance and knobby tires contribute to a combined fuel economy rating of just 16 mpg.

On the dirt the changes prove to turn it into a formidable machine. The power and 10 inches of wheel travel are more than adequate for climbing hills and storming fire roads, and the suspension proves to be a marvel in both situations.

GMC Sierra front

The 2022 GMC Sierra AT4X shows off its front fascia on the trail.

It's so well-behaved that it's hard to believe it doesn't have any computer control. It softly cradles the truck without bouncing as it rides over rolling whoop-de-doos and soaks up washboard surfaces and small jumps at higher speeds.

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A special Terrain mode for the traction management system holds on to low gears longer when you're in 4x4 Low to provide increased engine braking to mimic the sort of one-pedal driving electric cars are capable of.

The AT4X's limitations compared to the Raptor are evident, but pretty insignificant if you're not planning to go blasting through the desert at 100 mph, while its narrower stance makes it better for tight trails and parking at the mall.

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The main drawback is that, despite having all-weather floormats, the AT4X is so dressy you might be disinclined to get it dirty. I suggest you get over that feeling if you buy one, or else you won't really get what you paid for.

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2022 GMC Sierra AT4X

Base price: $77,395

Type: 5-passenger, 4-door 4x4 pickup

Engine: 6.2-liter V8

Power: 420 hp, 426 lb-ft

Transmission: 10-speed automatic

MPG: 14 city/18 hwy