GMC AT4 and AEV First Drives: The General Expands Its Off-Road Lineup

Montana is one of the most sparsely populated states in America, but it is also home to some of the most picturesque and pastoral landscapes the country has to offer.

Scanning the landscape in all directions reveal vistas replete with snow-capped Rocky Mountain peaks, rolling hills and a rugged wide-open territory that isn’t far removed from its wild west frontier-style heritage. During a recent visit, I half-expected to drive past grazing herds of Bison. That didn’t happen, but it wouldn’t have seemed strange if it did.

Given how much of its vast territory remains unspoiled, Montana is an outdoorsy person’s dream. From skiing, and snowmobiling, to fishing, hunting, and camping under its star-filled skies, the state offers much to those seeking to get outdoors and explore its rugged terrain.

And for those interested in doing some trail hunting, GMC has assembled a roster of off-road focused trims for its pickup family, which includes the mid-size Canyon, the light-duty full-size Sierra, and the heavy-duty full-size Sierra HD.

Back in 2019, GMC began rolling out the AT4 trim package for Sierra and, by 2021, for the previous generation Canyon, along with Acadia, Terrain, and Yukon SUVs. AT4 (all-terrain 4WD), was an off-road focused package that brought all-terrain tires, off-road suspension tuning, skid plating, tow hooks, among other equipment, designed to make GMC a more off-road capable brand.

Fast-forward to 2023, and the Canyon is all-new, and the Sierra and Sierra HD are recently refreshed, and now GMC has added AT4X trims alongside AT4.

Essentially, AT4X is GMC off-road turned up to 11. Each truck comes outfitted with gear designed for tackling the muddiest, rockiest, roughest, and wettest terrain one can throw at them.

Here's a quick summary of what each truck comes with:

Canyon AT4X

• 2.7-liter turbocharged 4-cylinder (310 hp / 430 lb-ft.)
• 10-speed automatic transmission
• 3-inch factory suspension lift
• Multimatic DSSV dampers
• Front and rear e-lockers
• Skid plates
• Transfer case shield and rocker protectors

Sierra 1500 AT4X

• 3.0-liter Duramax Turbo-Diesel inline 6-cylinder – 305 hp / 495 lb-ft. (6.2L V8 gas engine available – 420 hp / 460 lb-ft.)
• 10-speed automatic transmission
• Mulitmatic DSSV dampers
• Front and rear e-lockers
• Exterior AT4X badging

Sierra HD AT4X

• 6.6-liter V8 – 401 hp / 464 lb-ft. (6.6L Duramax Turbo-Diesel V8 available – 470 hp / 975 lb-ft.)
• 10-speed automatic transmission
• 18,500-pound max. towing capacity
• 1.5-inch factory suspension lift
• Multimatic DSSV dampers
• Rear e-locker
• 35-inch Goodyear Territory tires
• Unique upper and lower control arms and steering knuckles
• Larger steel transfer case skid plate and aluminum skid plate

American Expedition Vehicles (AEV) was founded in 1997 by Dave Harriton in Missoula, Montana with the aim of creating, in the words of company website, “performance-driven aftermarket parts and accessories for vehicles geared specifically to off-road recreational driving and overland adventure travel.”

AEV runs a design and warehouse facility in Missoula, and an engineering, vehicle build center, and warehouse, in Detroit. Over the years, the company has been mostly associated with products and accessories designed for Jeep and RAM vehicles, but it has expanded to include parts for the Ford Bronco, Toyota Tacoma, Chevrolet Colorado, and GMC.

For GMC, here’s what AEV brings to the table for each truck:

Canyon AT4X AEV

• 35-inch Goodyear Wrangler Territory MT tires with AEV in-bed vertical spare tire mount
• Updated fascia, larger front fender flares, wider tracks
• 4.5-inch factory suspension lift
• 12.2-inch ground clearance (best in class)
• Heavy duty AEV-stamped front bumpers with heavy duty recovery points
• Winch-capable rear bumpers
• Ultra-high strength boron steel skid plates
• AEV beadlock-capable Salta wheels
• AEV interior / exterior badging

Sierra 1500 AT4X AEV

• Five AEV stamped boron steel skid plates
• AEV-stamped steel rear bumper and front bumper with winch capability
• AEV racing-inspired Salta wheels with 12-spoke design and recessed valve stems
• Off-road rocker panel protectors for shielding sills and frame rails
• AEV interior / exterior badging

Sierra HD AT4X AEV

• AEV-stamped steel front and rear bumpers with winch capability
• AEV-stamped steel skid plates
• 18-inch 16-spoke Salta black gloss aluminum wheels
• AEV interior / exterior badging

During my two days in Montana, I drove four different GMC trucks. In order, it was the 2024 Sierra 1500 AT4X AEV, then the 2023 GMC Canyon AT4X, followed by the 2024 Canyon AT4X AEV, and finally the 2024 Sierra HD AT4X AEV.

I won’t dwell too much on the Sierra 1500, as seat time was limited, and on pavement only, from the Bozeman airport to the Montage Big Sky hotel for night one. Don’t get me wrong, the sand-colored Sierra is a fine truck, with a plush cabin and decent road manners. But its AEV add-ons were not put to the test in any way, as the 50-ish mile drive was all on pavement, so there isn’t much else to say.

Things changed considerably the following day, however, when we took the Canyons and Sierra HDs on some foreboding trails to put their off-road bonafides to the test.

First up were the two Canyons, which were chosen for the longer and more challenging trails. I drove a red AT4X tester first, which was used to climb up the trail, followed by a gray AT4X AEV, which was used to travel back to our lunch stop at the McAllister Inn.

The Canyon AT4X is quite a capable off-road truck. On the climb up, the trail went from mud to rock, and back to mud before finishing on a gravel berm, where our group was able to rest and take a few photos of the breathtaking mountain vista in the distance.

The trail is a narrow, rough-hewn path, where there’s only one lane, which means if you run into a few ATVs, or other vehicles, as we did, someone will have to pull over. In our case, we were able to squeeze by an ATV and couple of dirt bikes, but passing another vehicle would have been exceedingly difficult, and is only capable at a couple of points, mid-way near an abandoned mine, and at the top where there’s sufficient room to turn around.

Through it all, the Canyons managed to clamber over the rocks, ruts, tree branches and muddy, rocky terrain with ease. Most of the trek was in 4LO in terrain mode, with speeds not usually passing 8 or 10 mph, and during some stretches it barely exceeded 2 mph.

The two biggest assets, in my view, were high ground clearance (especially in the AT4X AEV), and the many camera views available. Being able to see in front, underneath, and to each side of the truck was invaluable for traversing such a challenging trail. Climbing down the trail was easier in the AT4X AEV, as the additional ground clearance, combined with downhill momentum pulled the truck along at a faster pace. At some points I was nearing 20 mph, but only briefly.

After lunch I drove the gray Canyon to XOverland Ranch in Three Forks, about 57 miles to the northeast where I drove a Sierra HD AT4X AEV on some very dusty trails over some grassy and hilly trails that included a 30-degree descent over broken shale. Unlike the Canyon trail, which was covered in thick vegetation and a very narrow path, this one was wide open. The challenge here was being able to see the truck in front, which was quite difficult due to the amount of dust each truck was throwing off.

To compensate, I had to keep my distance, and use my wipers to keep the dust out of my line of sight. That did the trick, and with the help of the Sierra’s many camera views, I was able to keep the truck on the single file path. Like the Canyon, the Sierra handled the trail with ease, thanks to its massive engine, ground clearance and all-terrain tires. Its massive size did present some difficulty at a few points along the way, but after getting used to its length and turning radius, sharp turns and uphill climbs were easier to navigate.

GMC, like many truck makers, sees big sales potential in the off-road / overlanding market, and the trucks it brought to Montana are quite capable of serving the growing sub-segment. Partnering with AEV, a well-known and trusted brand in the off-road market, will only help GMC earn credibility with off-roaders, whether they’re enthusiasts or newcomers.

These trucks don’t come cheap, but given their high degree of content, they should do good business for GMC. Given how many of its rivals are already in the segment, including its own sister brand Chevrolet, these AT4X and AT4X AEV models represent a smart move for the brand.

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