2026 GMC Sierra 2500 AT4: Specs, Features & Pricing

The 2026 GMC Sierra 2500 AT4 combines heavy-duty gasoline or diesel power with Rancho shocks, skid plates, an automatic locking rear differential and a leather-trimmed Crew Cab. It also includes substantial cabin and trailering equipment. However, the AT4 is a different specification from the more specialized AT4X, and its options deserve a close look.

This guide covers the Canadian Sierra 2500 HD AT4’s engines, towing information, fuel-economy limitations, interior, infotainment, safety and CAD pricing. The selected reference configuration is a four-wheel-drive Crew Cab with a standard bed and the gasoline engine.

Watch the 2026 GMC Sierra 2500 AT4 video

Models and configuration

The 2026 Sierra HD lineup includes Pro, SLE, SLT, AT4, Denali, AT4X and Denali Ultimate trims. Work-focused models and luxury configurations offer different cab, bed and equipment choices. In addition, the Sierra 2500 HD and 3500 HD have different weight and towing specifications despite sharing some trim names.

AT4 adds a dedicated appearance and off-road equipment package while retaining heavy-duty engine choices. The checked 2500 configuration has front bucket seats and a rear bench, creating a five-seat cabin. Its perforated front leather upholstery uses Jet Black with Kalahari accents. Confirm cab, bed and seating details on the exact vehicle rather than borrowing a Sierra 1500 AT4 specification.

2026 GMC Sierra 2500 AT4 engines

The standard 6.6-litre gasoline V8 produces 401 horsepower at 5,200 rpm and 464 lb-ft of torque at 4,000 rpm. It pairs with an Allison ten-speed automatic transmission and a 3.73 rear axle ratio. The checked gasoline truck has a 10,850-lb gross vehicle weight rating.

The optional 6.6-litre Duramax turbo-diesel V8 produces 470 horsepower at 2,800 rpm and 975 lb-ft of torque at 1,600 rpm. It also uses an Allison ten-speed automatic, with a 3.42 rear axle ratio. Diesel equipment includes an exhaust brake, engine block heater and a diesel exhaust fluid filler beside the fuel filler.

The Canadian trim selector lists a $10,995 difference between the gasoline and diesel starting configurations checked. However, the complete build determines the actual total and any equipment requirements. Compare the diesel’s purchase price, maintenance and fuel costs alongside its torque specification.

Chassis, suspension and wheels

Standard X31 equipment includes off-road suspension, twin-tube Rancho shocks, Hill Descent Control and skid plates. A two-speed Autotrac transfer case provides 2WD, Auto, 4WD High and 4WD Low settings. An automatic locking rear differential adds another traction-related component.

These are AT4 components. The AT4X uses a different suspension and tire package, so its lift, DSSV dampers and other specialized hardware should not appear as standard AT4 features. Similarly, an automatic rear locker should not be described as a front-and-rear locking axle system.

The checked AT4 has 20-inch high-gloss Black aluminum wheels with LT275/65R20 all-terrain tires. Red vertical recovery hooks, protective skid plates, a heavy-duty air filter and engine and transmission cooling equipment also appear in the standard specification. Tire and wheel choices can affect the final configuration.

Towing, payload and trailer equipment

For the selected gasoline Crew Cab, standard-bed AT4 4WD configuration, GMC’s builder displays 16,000 lb as its maximum trailering attribute. The summary does not identify the hitch category beside that number. Therefore, confirm whether the applicable rating is conventional, fifth-wheel or gooseneck before choosing a trailer.

The exact truck’s trailering information label provides ratings for different hitch types and tongue weight. Its payload label is equally important: occupants, cargo, accessories and trailer tongue or pin weight all use the available carrying allowance. A model-level maximum payload should not replace the label on a heavily optioned truck.

Standard equipment includes an integrated trailer brake controller, trailer hitch hardware with electrical connections, Hitch Guidance with Hitch View and an in-vehicle trailering app. GMC also lists trailer camera provisions and a bed-view camera. Accessory cameras, trailer sensors and compatible trailer equipment may still be necessary for particular functions.

The optional Max Trailering Package costs $1,775 in the checked builder and lists an 11,750-lb gross vehicle weight rating with a gooseneck/fifth-wheel preparation package. Availability and engine requirements must be checked before adding it. A separate Gooseneck Hitch Package appears at $500; preparation equipment and the hitch itself are separate items.

Fuel economy and ownership considerations

The Sierra 2500 HD AT4 is a heavy-duty pickup, and the 2026 NRCan light-duty guide does not provide a standard city, highway and combined rating for this model. Consequently, this article does not substitute a Sierra 1500 fuel figure or assign an unsupported L/100 km estimate.

The gasoline and Duramax diesel engines have different fuel and maintenance requirements. The diesel also uses diesel exhaust fluid. Towing, cold weather, cargo and idling can affect operating costs, so a useful budget starts with annual distance, trailer use and local fuel prices rather than an unrelated light-duty rating.

Interior and seating equipment

Standard perforated front leather bucket seats have heating and ventilation for both front occupants. GMC lists ten-way adjustment for each front seat, comprising eight-way power movement and two-way lumbar control. Driver memory, heated rear outboard seats and a heated steering wheel also appear in the standard equipment.

The steering column has manual tilt and telescoping adjustment. Dual-zone automatic climate control and rear air vents support cabin temperature control. A 60/40 rear bench includes seatback storage, a folding centre armrest and underseat storage, while the front console provides cupholders and device storage.

The specification also includes keyless entry and starting, remote start, a rear window defogger and a conventional auto-dimming interior mirror. A power-sliding rear window and Universal Home Remote belong to the optional $515 AT4 Preferred Package. This distinction helps when comparing a review vehicle with a base AT4.

Infotainment, displays and charging

Standard infotainment uses a 13.4-inch GMC Premium display with Google built-in. Wireless Apple CarPlay and Android Auto support compatible phones, while Bluetooth handles audio streaming and phone functions. A 12.3-inch digital Driver Information Centre provides configurable vehicle and warning information.

The AT4 includes a seven-speaker Bose system with a Richbass woofer, wireless phone charging and USB connections for front and rear occupants. Household-style 120-volt outlets appear in the cabin and bed equipment. Hotspot, navigation-related connected functions and satellite radio have data or subscription conditions that should be checked separately.

The $1,540 Technology Package adds a rear camera mirror and head-up display. These are optional on this AT4 rather than standard features inherited from AT4X or Denali Ultimate. The broader $4,005 AT4 Premium Plus Package also lists a power sunroof, power-sliding rear window and camera mirror among its equipment.

2026 GMC Sierra 2500 AT4 safety features

Standard Sierra HD Pro Safety includes automatic emergency braking, front pedestrian braking, forward collision alert, a following-distance indicator, IntelliBeam automatic high beams and lane-departure warning. Lane-departure warning alerts the driver; it should not be described as the lane-keeping steering assistance found in other GMC vehicles.

The AT4 also lists adaptive cruise control, front and rear parking assistance, HD Surround Vision, Trailer Side Blind Zone Alert and a Safety Alert Seat. Rear Cross Traffic Alert warns about detected crossing vehicles while reversing. Its name and description do not establish automatic rear cross-traffic braking.

Six airbags, StabiliTrak stability control, traction control, trailer sway control and Hill Start Assist provide additional protection and support. A tire-pressure monitoring system, rear seat reminder and Teen Driver functions also appear in the equipment list. Cameras and driver-assistance systems have operating limits, so the driver remains responsible for checking traffic and surroundings.

Bed and exterior convenience

The standard six-function GMC MultiPro tailgate supports several loading and access arrangements. A spray-on bedliner, cargo-bed LED lighting, side bed steps and CornerStep rear bumper also appear in the specification. The bed includes fixed cargo tie-downs.

Power-folding and extending vertical trailering mirrors include heated upper glass, lower convex sections, integrated lighting and auto-dimming upper glass. Rain-sensing wipers and LED headlamps complete further convenience equipment. Check optional steps and accessories on the order sheet rather than assuming every AT4 has the power-retractable steps of a different trim.

CAD pricing

The selected Ontario gasoline AT4 has a standard vehicle price of $98,399 CAD. The builder adds $2,700 freight, a $100 air-conditioning charge, $699 dealer fees, $22 OMVIC and $22.50 tire handling, producing an MSRP total of $101,942.50 CAD before sales tax.

The displayed $7,000 Non-Stackable Cash Delivery Allowance reduces that example to $94,942.50 CAD. It is a dated incentive and may not combine with other offers. The diesel starting configuration is $112,937.50 CAD before the displayed cash allowance, using the same listed starting-price comparison.

Paint, equipment groups and accessories can change the final price. Registration, insurance, sales tax and other excluded costs remain separate. Request a complete quotation for the actual truck and compare cash and financing terms without assuming every incentive applies to both.

Competition and buying priorities

The Chevrolet Silverado 2500 HD LT Trail Boss, Ram 2500 Rebel and Ford F-250 Tremor are relevant comparisons. Their suspension, axle systems, engines and cabin equipment differ. Also compare exact towing configurations and available payload before judging them by their badges.

Within GMC’s range, AT4X adds specialized chassis and cabin hardware, while Denali focuses on a different luxury presentation. AT4 buyers should decide whether Rancho suspension, the standard cabin features and the available Duramax meet their needs before adding costly packages. A complete build sheet and vehicle-specific capacity labels give the clearest purchase comparison.

Explore our other truck reviews to compare equipment and specifications.

Frequently asked questions

Is a diesel engine standard in Sierra 2500 AT4?

No. A 6.6-litre gasoline V8 with 401 horsepower and 464 lb-ft of torque is standard. The optional 6.6-litre Duramax diesel has 470 horsepower and 975 lb-ft.

Is Sierra 2500 AT4 the same specification as AT4X?

No. AT4 and AT4X have different suspension and equipment specifications. AT4X features should not be assigned to AT4 simply because the badges are similar.

Does the AT4 include heated and ventilated front seats?

Yes. The Canadian equipment list includes heated and ventilated perforated-leather front buckets, driver memory, heated rear outboard seats and a heated steering wheel.