2024 GMC Sierra 2500 AT4X Review and Test Drive

Upgrades to GMC's big truck make it an epic off-roader but compromise its work capabilities.

Tim Stevens | 

May 1, 2024 | 10 min read

Tim Stevens

The capability, luxury, and entry prices of modern pickups just keep climbing. There's seemingly no ceiling to what buyers expect from today's trucks, which offer more towing, payload, comfort, and technology than we could have foreseen a decade ago.

Off-road capability is also on the menu, and sitting near the top of that list is the 2024 GMC Sierra 2500 AT4X. It's impossible to miss, and with its lifted Multimatic suspension drivers will be able to look down on everything around them — including machines that require a commercial driver's license to operate.

The AT4X, especially with the AEV package, is a heavy-duty work rig loaded with off-road hardware, tailgate niceties, and interior luxuries. It’s GMC's version of the ultimate truck — and I spent a week testing it to see if the description fits.

Tim Stevens

The GMC Sierra 2500 AT4X Starts at More Than $80,000

The 2024 GMC Sierra 2500 Heavy Duty (2500HD) comes in numerous configurations and trims, starting with the Regular Cab Long Bed Pro 2WD priced from the high $40,000s. From there, you have various permutations of double cabs and crew cabs with either the standard or long cargo bed, available with either two- or four-wheel drive.

Pro is the base trim, followed by SLE, SLT, AT4, Denali, and AT4X. The top-shelf Denali Ultimate caps the lineup with a starting price in the high $90,000s, including the $1,895 destination to ship the truck from the Flint, Michigan, factory that builds it to your local dealership.

For this 2024 Sierra 2500HD review, I test-drove a Crew Cab AT4X in upstate New York. Highlights from the optional equipment list included a Duramax turbo-diesel 6.6-liter V8 engine, the AT4X AEV package, and Sterling Metallic paint. The manufacturer's suggested retail price was $103,075, including the destination charge. GMC provided the vehicle for this Sierra 2500 AT4X review.

Tim Stevens

The Sierra 2500 AT4X Is Tall and Imposing

The Sierra 2500, lifted in AT4X trim, is utterly imposing. At 6 feet tall, I can barely look into the engine bay, never mind reach the dipstick. That size and height alone are enough to make quite an impression, but GMC didn't stop there.

This example has the AEV package, which adds a huge dose of off-road protection and styling. It includes stamped-steel front and rear bumpers perforated with numerous attachment points for lights and recovery accessories, stamped-steel skid plates, and 18-inch black wheels.

The result is quite striking, but if you can manage the climb to the cabin, you'll find a fairly traditional layout. Yes, the AT4X trim gets some extra badging here and there, plus a few AEV logos on the headrests. But by and large, it's the standard Sierra 2500, which is to say it's expansive.

Tim Stevens

With wide expanses of black vinyl carrying various embossings and color-contrasting stitching, the materials are a mixed bag. There are acres of black plastic, some of which has a soft-touch coating, but much of it feels harsh and brittle. The headliner, at least, is of a plush microfiber.

The dashboard is riddled with buttons, as is typical for this vehicle class, but the layout is logical for the most part. Controls for the four-wheel-drive (4WD) system — including the transfer-case settings — are intuitively located to the left of the steering wheel on the dash. A simple drive mode toggle also cycles through on-, off-road, and towing modes.

Instead of sitting on the dash as in most trucks, the trailer brake control is next to your right hip. This makes it easy to access should you tow something requiring extra finesse.

Tim Stevens

Comfort Is Thanks to the Sierra 2500 AT4X Interior Volume

Climbing into the Sierra 2500 AT4X is no small task. The power-deploying running boards help, but anyone with bad knees, hips, or other mobility issues will likely struggle to make this ascent regularly.

Inside, you'll find roomy seating for five. With generous legroom, headroom, and shoulder room, three adults should be comfortable in the rear seats — though they might fight over the two USB ports. There's one A and one C. The outer two seats are heated.

Both seats up front are heated and ventilated, and GMC also heats the steering wheel. The driver's seat is a long reach from the passenger's seat, so there are no worries about accidentally rubbing elbows across the wide armrest. The front seats don't offer much bolstering or support, but they are comfortable and even offer massaging.

Inside the center armrest, you'll find another pair of A and C USB ports, a wireless charging pad, and a three-prong electrical outlet for bigger devices.

Tim Stevens

Cargo and Capability Abound in the Sierra 2500 AT4X

Storage space is abundant inside the Sierra 2500's cabin. The center armrest features enough space to hold a roasted chicken. The glovebox is cavernous and is paired with a smaller, separate compartment above it on the dashboard.

All four door panels have pockets big enough for your thirstiest water bottles plus space for tools, iPads, hats, and gloves. Flipping up the rear seats reveals another set of storage cubbies.

The real cargo is what you put in the back of the truck. The Sierra 2500 in Crew Cab configuration can haul up to 4,178 pounds of payload. Unfortunately, the AT4X AEV comes nowhere close to that, maxing out at 1,380 pounds, or about 200 pounds less than a Honda Ridgeline.

Access to that bed is made easier thanks to GMC's MultiPro tailgate, which flips down in myriad ways to aid in climbing into or supporting cargo already in there. The only issue is that, even with it folded down to serve as a step up, it's still a challenge to get in thanks to the extreme lift on the AT4X.

The AT4X in AEV trim can tow 18,500 pounds. If towing is your priority, go for a lower-spec crew cab, which offers the 2500's maximum rated towing of 22,430 pounds.

Tim Stevens

Google Found Onboard the 2024 GMC Sierra 2500 GMC

The 2024 GMC Sierra 2500 AT4X uses the GMC Premium Infotainment System with Google built-in. It's clean, responsive, and makes good use of the truck's 13.4-inch touchscreen.

Sign in with a Google account, and you have access to your contacts, addresses, appointments, and reminders. With its quick and easy route planning, numerous available parameters, and real-time re-routing based on traffic, the Google Maps navigation is about the best I've experienced in a vehicle.

Likewise, I found the Google Assistant's voice recognition to be excellent, as it handled nuanced requests such as "I'm hungry" and lengthy, confusing addresses without issue. If you prefer Amazon's Alexa, GMC has built that in as well.

However, neither can handle in-car settings such as seat heaters or temperature controls, meaning you'll have to reach for one of the many buttons or knobs.

Built-in apps — including Google Podcasts and Spotify — are available, but Android Auto and Apple CarPlay smartphone projection are available wirelessly. There's also an integrated high-speed connection and access to a Wi-Fi hotspot.

Media plays through a 12-speaker Bose sound system much like this truck: big and powerful but — in my opinion — lacking in finesse. A second sound system is built into the cargo bed for tailgating.

Tim Stevens

The 2024 GMC Sierra 2500 AT4X Is Abuzz With Safety Tech

The 2024 Sierra 2500 includes the Sierra HD Pro Safety suite, which includes forward-collision warning with pedestrian detection and automated emergency braking, lane-departure warning, blind-spot monitoring with a rear cross-traffic alert system, and a surround-view camera.

Instead of — or in addition to — incessant audio warnings, the Sierra uses GMC's Safety Alert Seat, which buzzes on the left or right to alert when, for example, the truck wanders out of the lane to the left or right. Given the width of this truck and the lack of active steering assist, you're likely to get buzzed a lot on narrow country lanes.

The adaptive cruise control works well, spotting slower traffic ahead early enough to smoothly bring this behemoth down to match their speed.

Neither the National Highway Traffic Safety Administration nor the Insurance Institute for Highway Safety has provided safety ratings for the 2024 GMC Sierra 2500 yet.

Tim Stevens

There's a Big Diesel With Massive Torque in the Sierra 2500 AT4X

When equipped with the Duramax turbocharged 6.6-liter V8 diesel engine, the Sierra 2500 produces 470 horsepower and 975 pound-feet of torque. That power is sent through a 10-speed automatic transmission and a two-speed, selectable transfer case with high and low gearing.

It's no demon in terms of acceleration, but the focus is on towing and torque. I found the 10-speed transmission remarkably smooth, as it switches ratios almost imperceptibly. It's also eager to upshift the 6.6-liter diesel to save fuel, which is more effective than expected.

Tim Stevens

When Too Much Is Too Much

The 2024 GMC Sierra 2500 AT4X is one of those trucks you don't want to drive angry. Or tired. Or anything other than completely alert and patient. You need to be well aware of what's happening around you before setting this machine in motion.

While the parking and other sensors will help to some degree and visibility to the sides is generally good, the extreme hood height of this lifted 2500 means that even a tall adult could be standing right in front of you, and you'd never see them.

The surround-view camera helps, but that only toggles if you're in reverse. Unfortunately, there's no physical button for that. You'll have to find it on the touchscreen, which I found to be a hassle.

In motion, you'll still need to be on your toes because turning and braking require some forward thinking. The steering is slow, and you'll have to consider the truck's length for tight turns. The handling is predictable, however, and the 2500 is perfectly drivable. It's just not easy to wield in tight situations.

Tim Stevens

This truck can haul 1,380 pounds, much less than you might expect. With an empty cargo bed, it bounces and crashes over most bumps. The brake pedal travel is long and feels soft, but the truck does stop without drama.

Unfortunately, I wasn’t able to evaluate the performance of the AT4X off-road. My testing antics were limited to a well-groomed logging road. The AT4X did just fine, but that was hardly a test for the Multimatic suspension.

I was relieved I didn't take this truck too far out into the wilderness. My usual testing grounds feature long, narrow trails with few small outs for stopping or turning around. This rig would have barely fit on many sections, and the idea of turning it around seems like a nightmare.

Tim Stevens

The Sierra 2500 AT4X Is Comprehensive but Compromised

All told, I'm lost on the point of the Sierra 2500 AT4X. The Sierra 2500HD, in my experience, is among the most comfortable and capable full-size work trucks, and with its lifted suspension, the AT4X package adds some significant off-road chops to the equation.

But this truck is so huge that navigating many off-road trails would be a challenge. Meanwhile, adding that off-road suspension compromises its towing and hauling capabilities, not to mention making it something of a chore to do everything from loading cargo into the bed to loading yourself into the cab.

All that and a six-figure price tag leave me thinking there are better options. A lower-spec Sierra is a better work truck, while there are plenty of smaller, more capable off-roaders if that's your goal. This truck feels like it's trying to do too much, which is a good way of describing it: too much.

Tim Stevens

Tim Stevens is a veteran editor, analyst, and expert in the tech and automotive industries. He helmed a major website's automotive coverage for nine years and acted as its content chief. Prior to that, Tim served as the editorial lead at a tech-oriented site and even led a previous life as an enterprise software architect.