2021 GMC Sierra 2500HD

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  • Overview

    A black 2021 GMC Sierra 2500HD is angled left.

    Who says work trucks can't be fun? The 2021 GMC Sierra 2500HD takes exception to this commonly-held notion and puts it to the test with a highly capable truck that's been constructed to take on some pretty tough jobs… all without sacrificing the comfort of the driver.

    As a rule, trucks with HD in the name are big. They're bulky, noisy, and all for a good reason - they need to do really big jobs. Common sense says you can't carry massive payloads or tow giant trailers with dainty wheels and delicate motors. But getting the rugged capabilities that you need should not mean that you have to give up the pleasure of a comfortable seat, a cabin where all the features are neatly laid out where the driver needs them, and technology that puts the "fun" back in "functional." The 2021 GMC Sierra is engineered to be driven by actual humans with actual needs but never loses sight of the goal: to work hard and work well with every turn of the key.

    445 - 910

    Torque (lb-ft)


    Max Payload (lbs)


    Max Towing (lbs)

    Starting at


  • Capability

    A white 2021 GMC Sierra 2500HD AT4 is shown from the side towing two UTVs.

    If you're in the market for a heavy-duty truck, the numbers matter. You need to know that you'll be able to get the job done right, on time, and make it to the worksite every day, regardless of the terrain or weather. GMC has taken all of this information into consideration when designing the 2021 Sierra 2500HD, offering the truck in Regular cab, Crew cab, and Double cab configurations.

    Regular Cab

    Regular cab models come standard with rear-wheel drive and an 8-foot bed, but four-wheel drive is available on most trims. These models have a ground clearance of 10.19 inches and a roomy wheelbase of 141.55 inches. The Regular cab models can accommodate up to 83.5 cubic feet of cargo, with a maximum payload weight of 3,979 pounds. A properly equipped Sierra 2500HD with the Regular cab configuration can tow up to 14,500 with a conventional hitch and up to 18,510 with a gooseneck or fifth-wheel hitch.

    Crew Cab

    If you regularly have company on the trip to and from the job, you'll want to check out the Crew cab models of the Sierra 2500HD. The Crew cab is also offered in rear-wheel or four-wheel drive, and a choice between a 6-foot 9-inch standard bed or the 8-foot bed. The standard bed models have a wheelbase of 158.94 inches, while the long bed stretches out to a total of 172 inches. Both bed types have a ground clearance of over 10 inches. Cargo space for the standard bed is reduced to 69.6 cubic feet, but the payload maximum drops only slightly, from 3,862 pounds to 3,760 pounds. Crew cab models have the capability of towing up to 18,500 pounds regardless of hitch type.

    Double Cab

    The Double cab models demonstrate GMC's ability to offer trucks in various configurations without changing capability. Also available with a standard or long bed, the Double cab models of the 2021 GMC Sierra 2500HD maintain towing maximums of 18,200 pounds for fifth-wheel and gooseneck hitches and 14,500 pounds for conventional hitches. The wheelbase spans from 149.4 inches for standard bed versions, with the long bed bringing that measurement up to 162.48 inches. Ground clearance remains above 10 inches, as well.

  • Work

    A close up shows the hood scoop and grille on a red 2021 GMC Sierra 2500HD.

    Of course, it's important that a big truck like the 2021 GMC Sierra 2500HD has enough power for work and play. Under the hood is one of two 6.6L V8 engines. The standard engine is a gasoline model, though a turbo-diesel version is optional. The gasoline version deserves plenty of attention, with 401 horsepower and 464 lb-ft of torque, accompanied by a 6-speed automatic transmission. The turbo-diesel is a force to be reckoned with, however, thanks to 445 horsepower and a whopping 910 lb-ft of torque. This engine is joined by a 10-speed automatic transmission from Allison, as well as a Dual Path Air Induction System designed specifically for this engine to maximize horsepower and increase performance while trailering.


    Trailering is one of the primary functions of a heavy-duty truck, and it's hard to find a truck more equipped for pulling than the 2021 GMC Sierra 2500HD. Trailering mirrors are standard, as is the Side Bed Step that allows easy access to the bed even when you have a trailer attached. Drivers can add a variety of options to the Sierra 2500HD to amp up the trailering experience, including power extending mirrors, LED rear guidance lamps, and amber roof markers. However, the ultimate trailering feature is the high definition Surround Vision system that provides a 360-degree view of your surroundings. This system can even show you the inside of your trailer and can fuse multiple camera angles to make your trailer "disappear," allowing you to see what is directly behind you.


    For drivers who find themselves in the mud, rocks, or streams - either for work or play - the AT4 trim also adds features that can make a driver's relationship with their truck that much better. This package adds off-road suspension, twin-tube Rancho shocks, an automatic locking rear differential by Eaton, and underbody skid plates. The result is a work-ready beast that can travel almost anywhere.

  • Comfort

    A close up shows the black and orange rear leather seats in a 2021 GMC Sierra 2500HD AT4.

    For some drivers, performance and power are enough excitement. But for those who spend long hours on rough roads, the interior of the 2021 GMC Sierra 2500HD might be the highlight of a never-ending workday. Unlike many work trucks, the Sierra 2500HD is offered in several trim levels, ranging from the base HD to the opulent Denali.

    A Trim For Every Use

    Standard offerings include all the basic necessities, including an easy-to-clean vinyl interior, LED headlights, taillights, and daytime running lights. However, you will also find a rearview camera, a 7-inch infotainment center with touchscreen, cargo area light with corner step and bed step, and two USB ports.

    Stepping up to the SLE trim adds cruise control, Wi-Fi, Onstar, and the Multi-Pro tailgate, which offers several configurations to help you with a variety of tasks. The flooring is carpeted, the steering wheel is wrapped in leather, and the side mirrors are power-adjustable.

    The SLT trim is where comfort really starts to take over, with heated and power-adjustable seats and steering wheel, a self-dimming rearview mirror, and SiriusXM satellite radio. In-cab storage is increased with hidden under-seat space, and dual-zone automatic climate control does the work while you drive in comfort.

    The AT4 is typically described as "action-ready." This off-road trim comes standard with four-wheel drive and a two-speed transfer case. It's also equipped with skid plates and off-road suspension with Rancho shock absorbers. However, this capability doesn't mean the AT4 isn't comfortable. The seats are trimmed in leather, with the front bucket seats enjoying heat and ventilation, and even the rear outboard seats are heated, providing an end to achy backs and cold seats in the winter.

    The Denali

    At the top of the lineup is the Denali trim, which reinforces the reputation that name has gained. While the other trims ride high on 17" wheels, the Denali towers above on 20" alloy wheels. The driver assistance features are expanded to include navigation, trailer and bed view cameras, a 360-degree surround view system, as well as front and rear parking sensors. Inside the cab, drivers will find an interior clad in real wood, aluminum, and chrome, with leather seating in front and rear. As with the AT4, the front and outboard rear passenger seats are heated, with additional rear legroom. Wireless device charging and a premium Bose sound system take the truck from "comfortable" to "functioning office space."

    The Denali can be customized with even more luxurious features, many of which are also available as options on other trims. The Denali Black Diamond Edition adds a variety of workplace-ready features, such as LED perimeter lighting, auxiliary trailer camera, a trailer tire pressure monitoring system, and power-retractable steps. There is even a Kicker audio system for even more sound options.

    GMC's first-in-class 15-inch diagonal head-up display is also an available option on the Denali trim. This display allows drivers to project crucial details such as speed, navigation, driver assistance alerts, fuel monitoring, and tilt and angle via the off-road inclinometer feature. With all of these features, the days of the "all work and no play" heavy-duty trucks are in the past, and drivers will relish the commute, thanks to GMC's well-designed driver-friendly Sierra 2500HD.

Colonial Motor Mart 40.627844, -79.145080.