2026 GMC Sierra 2500 AT4X: Specs, Features & Pricing

The 2026 GMC Sierra 2500 AT4X combines heavy-duty truck capability with a dedicated off-road chassis and a premium five-seat cabin. Its factory lift, Multimatic DSSV dampers, rear locking differential and mud-terrain tires distinguish it from the regular AT4. Inside, full-grain leather, massaging front seats and a 12-speaker Bose system add comfort equipment beyond a basic work truck.

This guide covers the Sierra 2500 HD AT4X Crew Cab with the standard bed and four-wheel drive. It compares the standard gasoline V8 with the optional Duramax diesel, then examines towing, fuel-economy information, safety, infotainment, interior features and CAD pricing.

Models and configurations available

The 2026 Sierra 2500 HD range includes Pro, SLE, SLT, AT4, Denali, AT4X and Denali Ultimate. Cab, bed and engine availability vary by trim. The reviewed AT4X configuration uses a Crew Cab, standard-length bed, front bucket seats and a rear bench for five occupants.

AT4X has its own suspension and equipment specification. A regular AT4 uses different off-road hardware, while Denali emphasizes another premium presentation. The optional AT4X AEV Edition adds further protection and exterior equipment. It is a package beyond the standard AT4X.

Sierra 1500 AT4X and Sierra 2500 HD AT4X also use different engines, dimensions and capability ratings. A specification from the lighter truck should not be carried over to this heavy-duty model.

Engine specifications

Standard 6.6-litre gasoline V8: 401 hp at 5,200 rpm and 464 lb-ft at 4,000 rpm. It pairs with an Allison-branded ten-speed automatic transmission and a 3.73 rear axle ratio in the selected configuration.

Available 6.6-litre Duramax turbo-diesel V8: 470 hp at 2,800 rpm and 975 lb-ft at 1,600 rpm. It also pairs with an Allison ten-speed automatic, with a 3.42 axle ratio in the selected diesel configuration. The diesel includes an exhaust brake and uses Diesel Exhaust Fluid, with its fill point at the fuel door.

Tow/Haul mode and automatic grade-braking functions form part of the transmission specification. Four-wheel drive, a two-speed Autotrac transfer case and a driver-selectable rear electronic locking differential are standard AT4X equipment. There is no hybrid powertrain in this Sierra HD range.

AT4X suspension and exterior hardware

The AT4X has a factory-installed 1.5-inch suspension lift and Multimatic DSSV dampers. Front aluminum and transfer-case steel skid plates provide underbody protection. Hill Descent Control, a heavy-duty air filter and red recovery hooks are part of its off-road specification.

Standard 18-inch machined wheels have High Gloss Black accents and LT305/70R18 mud-terrain tires, marketed as 35-inch tires. The rear electronic locker is part of the HD AT4X equipment. This truck’s specification should not be confused with the front-and-rear locking setup of a different AT4X model.

The optional AEV Edition adds stamped steel bumpers, additional protective hardware and AEV wheels and identification. Package content changes the truck’s weight and final price. Buyers should verify the completed vehicle’s loading information after choosing that equipment.

Towing and payload

GMC’s configurator lists 16,000 lb of maximum trailering for the selected gasoline AT4X Crew Cab standard-bed 4WD. Selecting the Duramax diesel changes its listed maximum to 18,500 lb. These figures describe the selected configurations and do not mean every Sierra 2500 has the same rating.

GMC’s Canadian truck comparison identifies 18,500 lb as the AT4X maximum conventional trailering figure. Confirm the separate fifth-wheel or gooseneck limit for the exact truck and hitch arrangement. A higher advertised Sierra HD range maximum may require a different model, engine or configuration. It should not replace the AT4X-specific rating.

Standard trailering equipment includes a 2.5-inch receiver with a two-inch insert, four- and seven-pin connections, an integrated trailer brake controller and the ProGrade Trailering System. Hitch Guidance with Hitch View and the in-vehicle Trailering App assist with setup and monitoring.

HD Surround Vision, a Bed View Camera and trailer camera provisions offer useful views. Some functions require an auxiliary camera or trailer sensors. A gooseneck hitch package is optional. Passengers, cargo, accessories and hitch weight all use payload, so rely on the individual vehicle’s loading label rather than a generic maximum.

Fuel economy and operating costs

The Natural Resources Canada 2026 Fuel Consumption Guide does not list a Sierra 2500 HD AT4X city, highway or combined rating. The Sierra 1500’s fuel figures therefore cannot be used for this truck. A precise official L/100 km number would be misleading without a rating for this model.

The gas and diesel engines also have different fuel and maintenance requirements. Diesel ownership includes DEF use, while actual consumption depends heavily on trailer weight, cargo, speed, temperature, terrain and idling. Calculate costs using the intended workload and fuel type rather than an unrelated light-duty pickup’s laboratory figure.

For a truck that regularly tows, compare engine price, fuel expense, maintenance and the required towing configuration together. A purchase-price difference alone cannot establish which engine will cost less over your ownership period.

Interior, seats and storage

AT4X uses an Obsidian Rush cabin with full-grain leather, technical-grain accents and authentic Vanta ash wood. Sixteen-way power front seats include lumbar adjustment and massage. Front-seat heating and ventilation, heated rear outboard seats, a heated steering wheel and driver memory are standard.

The Crew Cab rear bench folds in a 60/40 split and includes seatback and under-seat storage. A centre armrest provides cupholders, while the front console includes trays and everyday storage. Dual-zone automatic climate control and rear air vents serve the cabin.

Remote start, keyless entry, a power-sliding rear window, premium floor liners and a power sunroof are included in the reviewed standard specification. The steering column has manual tilt-and-telescoping adjustment. Confirm the equipment list when comparing it with another Sierra trim.

Black power-retractable assist steps with perimeter lighting help cabin access. A spray-on bedliner, side bed steps, rear CornerSteps and LED cargo lighting support bed use. The six-function MultiPro Tailgate includes a Kicker audio system that operates independently of the cabin sound system.

Infotainment and technology

The standard 13.4-inch GMC Premium Infotainment touchscreen includes Google built-in compatibility, wireless Apple CarPlay and wireless Android Auto. A 12.3-inch digital Driver Information Centre displays vehicle information. A 15-inch multicolour head-up display is standard on this AT4X.

The 12-speaker Bose Premium Series system includes CenterPoint processing and a Richbass woofer. Wireless phone charging, USB connections and 120-volt outlets in the cabin and pickup bed are included. Apps, hotspot use and connected services depend on compatible devices, network coverage and service terms.

A Rear Camera Mirror provides the option of a camera-based rearward image. The surround-view and bed cameras support manoeuvring and checking cargo. Advertised additional trailer views need the necessary equipment, so the maximum number of views should not be assumed to work with every trailer.

Safety and driver assistance

Sierra HD Pro Safety includes Automatic Emergency Braking, Forward Collision Alert, Front Pedestrian Braking, a Following Distance Indicator, Lane Departure Warning and IntelliBeam automatic high beams. Lane Departure Warning alerts the driver; its name should not be changed to a different lane-centering system.

The reviewed AT4X includes Adaptive Cruise Control, Front and Rear Park Assist, HD Surround Vision, a Bed View Camera, Trailer Side Blind Zone Alert and Rear Cross Traffic Alert. These named alert systems are distinct from rear cross-traffic automatic braking fitted to some other GM models.

Six airbags, stability control, traction control, trailer sway control, Hill Start Assist, Teen Driver and a rear-seat reminder provide additional safety functions. Camera and assistance systems have operating limits and require an attentive driver. Check the final window label for the exact truck.

Pricing in CAD

GMC listed the selected gasoline AT4X at a standard vehicle price of $114,599. Freight of $2,700, air-conditioning tax of $100 and displayed Ontario dealer and regulatory fees brought it to $118,142.50 before sales tax, without added options.

The Duramax diesel option added $10,995, for a displayed total of $129,137.50 before sales tax. The selected diesel configuration also listed its related axle, exhaust brake, block heater and other equipment. Compare the complete configuration when pricing engines.

A $7,000 non-stackable cash delivery allowance reduced the displayed net amounts to $111,142.50 for gas and $122,137.50 for diesel before sales tax. These are time-sensitive offers with eligibility and payment-method conditions, not permanent starting prices.

Listed packages included the Gooseneck Hitch Package at $500, Cargo Convenience Package at $920 and AT4X AEV Edition at $10,930. Dependencies and accessories can change the quote. Confirm the same cab, bed, engine and package specification before comparing dealer prices.

Competition

Chevrolet Silverado 2500 HD ZR2 is a closely related off-road HD alternative. Ram 2500 Power Wagon and Rebel, and Ford F-250 with appropriate off-road equipment, provide other choices. Their engine availability, equipment and towing priorities differ, so compare the exact configurations rather than badges alone.

Within GMC’s range, regular AT4 may provide the desired styling and equipment at a lower price. Denali and Denali Ultimate offer different premium specifications. AT4X combines the dedicated chassis hardware with a high level of cabin equipment. Browse our other truck reviews for more choices.

Watch the Sierra 2500 AT4X video

Frequently asked questions

How much can the 2026 Sierra 2500 AT4X tow?

The selected gas Crew Cab standard-bed 4WD lists 16,000 lb, while the Duramax diesel configuration lists 18,500 lb. GMC identifies 18,500 lb as the AT4X maximum conventional trailering figure. Fifth-wheel and gooseneck limits need a separate check for the actual truck.

What is the official fuel economy of the Sierra 2500 AT4X?

NRCan’s 2026 Fuel Consumption Guide does not list a city, highway or combined rating for this heavy-duty AT4X. Sierra 1500 fuel figures do not apply; trailer weight, cargo and operating conditions have a large effect on fuel use.

Does the Sierra 2500 AT4X have front and rear locking differentials?

The HD AT4X specification includes a driver-selectable rear electronic locking differential. Do not carry over the Sierra 1500 AT4X’s front-and-rear locking arrangement to this truck.