A white 2023 GMC Sierra 2500 HD AT4 is shown parked off-road.

Conquer the Trails in a 2023 GMC Sierra 2500 HD AT4

With a name meaning “all-terrain four-wheel drive,” the GMC Sierra 2500 HD AT4 has become the standard for heavy-duty off-road trucks. GMC introduced the AT4 trim with the 2019 Sierra 1500 full-size truck before extending it to its lineup of heavy-duty trucks. In so doing, GMC has given off-road enthusiasts a big truck option that most other automakers lack. The 2023 GMC Sierra 2500 HD AT4 comes in as the most advanced model yet in this truck’s venerable history.

The AT4 model of the 2023 Sierra 2500 HD gives drivers all the capabilities of a heavy-duty truck while also providing the added benefits of a vehicle ready to take on the trail right off the lot. This means that you get the towing and hauling capability you need with the ability to take your truck off-road. The GMC Sierra 2500 HD AT4 is ideal for people who love to camp and fish. You can take a camper or a boat into remote, hard-to-get-to areas for the best experience possible. With the power of the GMC Sierra’s engine options, you can tow heavy trailers, maximizing your enjoyment and usage of your truck.

A white 2023 GMC Sierra 2500 HD AT4 is shown driving off-road.

Ready for the Great Outdoors

Before you take a truck off-roading, you want to be certain it has the equipment to handle the trail. GMC named the AT4 for its all-terrain four-wheel drive because they gave the Sierra 2500 HD AT4 all of the features you’ll need to make trail running enjoyable in your truck. It starts with a four-wheel drivetrain that provides the truck with exceptional traction. This includes an Autotrac two-speed transfer case with push-button controls, allowing you to shift to two-wheel drive for better performance and fuel economy on roads and four-wheel drive for off-road and inclement weather traction. This transfer case helps deliver the proper amount of horsepower to each wheel on your GMC Sierra 2500 HD AT4.

The AT4 also features an automatic locking rear differential—an Eaton Locker that can sense the difference in wheel speed up to 100 RPM. When this happens, it will lock the rear wheels, so they move in unison. As a result, you will get the traction you need to get out of dense sand and thick mud.

GMC has equipped the 2023 Sierra 2500 HD AT4 with a specialized off-road suspension featuring Rancho shock absorbers. This will give you and your passengers a comfortable ride no matter the conditions you encounter. There is also a Hill Descent Control, which uses the antilock braking system to provide better control when taking your truck downhill. The system works the brakes so you can focus on steering; all you have to do is push the Hill Descent Control button, and the system will take over braking from you.

The GMC Sierra 2500 HD rides on a set of 18-inch machined aluminum wheels fitted with all-terrain tires, giving you exceptional grip both on and off the road. The truck also has an impressive 10.12 inches of ground clearance, which should give you plenty of room to pass over most obstacles in your path. However, some obstacles are always a problem when off-roading, especially those that you cannot see; the last thing you want to have happen out on the trail is for your truck to run over a rock or log and damage a vital part of your truck’s undercarriage. Thus, GMC has placed steel skid plates in strategic positions throughout the AT4’s underside to protect such critical points as the oil pan, differential case, front underbody, and transfer case. This will give you the peace of mind that you can take your GMC Sierra 2500 HD AT4 almost anywhere.

Another hazard of off-roading is getting your truck stuck in a rut or a muddy patch. When this happens, you may need a winch or other vehicle to tow you out of your predicament. The issue is that you don’t want a tow to damage your vehicle—hence why GMC has attached a pair of red recovery hooks to the front end of the Sierra 2500 HD AT4. These red hooks not only look cool but can also help get you out of a tough jam.

A white 2023 GMC Sierra 2500 HD AT4 is shown towing a trailer on a muddy path.

A Sumptuous Pair of Engines

You need a powerful engine to move a big truck, and GMC gives you two choices on the Sierra 2500 HD. The standard engine is a 6.6L V8 gas engine that comes with a six-speed, heavy-duty, electronically controlled automatic transmission. This engine has a cast iron block with cast aluminum cylinder heads, and it utilizes direct fuel injection to deliver up to 401 hp at 5200 RPM and 464 lb-ft of torque at 4000 RPM.

The alternative engine for the Sierra 2500 HD is a 6.6L Duramax Turbo-Diesel V8 paired with an Allison ten-speed automatic transmission. This transmission has an Auto Grade Braking system that automatically downshifts on downslopes to reduce brake wear and tear. The engine comes with an engine block heater, which will come in handy in cold weather to help keep the diesel oil in a liquid state. It also utilizes common-rail direct injection to provide up to 445 hp at 2800 RPM and 910 lb-ft of torque at 1600 RPM.

No matter which engine you choose, you are going to be impressed with the GMC Sierra 2500 HD AT4’s capabilities. If you need to carry a heavy load, you can fit up to 3,751 lbs of cargo in the AT4’s bed—with the gas engine—and 3,553 lbs of payload with the turbo-diesel engine. If you plan to do significant amounts of hauling, you can change the standard 81-inch bed to a 98-inch long one; this will give you 83.5 cu.ft. of cargo space, with the ability to haul 3,800 lbs of cargo with the gas engine and 3,536 lbs with the available turbo-diesel engine. GMC has equipped this truck with its MultiPro Tailgate, making loading and unloading your payload bed easier.

The Sierra 2500 HD AT4 is also a solid choice for trailering. Unlike hauling, choosing the available turbo-diesel will give you more towing capability, towing up to 18,500 lbs. Choosing the gas engine will reduce this to a still capable and impressive 14,500 lbs. All 2023 GMC Sierra 2500 HD AT4 models come with the trailering package, which adds a trailer hitch, platform, a 2.5-inch receiver hitch, four- and seven-pin connectors, and a seven-wire electrical harness with a seven-pin sealed connector that allows you to link the trailer to the truck’s lights and brakes. You also get the Hitch Guidance System and HD Surround Vision Camera, which includes two trailer view cameras; these will help you when you need to hook up and unhook your trailer, back your truck up when you are towing, and change lanes on a busy highway.

The black interior and dash of a 2023 GMC Sierra 2500 HD AT4 is shown.

Room for the Whole Crew

GMC has made the Crew Cab standard on the AT4 model of the 2023 Sierra 2500 HD. This provides seating for up to five passengers, with a pair of bucket seats up front and a comfortable set of seats in the back. The front seats are ventilated, and the front and rear outboard seats are heated. These seats feature perforated leather for added comfort and luxury—a nice touch on an off-road model. There is also plenty of legroom inside the AT4, with a full 40.12 inches in the front and 43.4 inches in the back. (This should reduce the chances of your passengers fighting over who gets to ride a shotgun!)

An Off-Road Warrior Built for Trucking

The 2023 GMC Sierra 2500 HD AT4 is not a one-trick pony. This is not just a truck to take out off-roading on the weekends, while you use another truck during the week. The 2500 HD AT4 has the towing and hauling capabilities you need to get the job done, as well as the interior comfort in its Crew Cab, which makes it ideal for use as a family vehicle.

But you shouldn’t forget that the Sierra 2500 HD AT4 is built rugged for the great outdoors; it has that four-wheel drive, skid plates, and other features for a reason—it wants to be out there, getting dirty. So, get a 2023 GMC Sierra 2500 HD AT4 and see how far you can push your limits!