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GMC Sierra Heavy Duty


Recently, Modern WorkTruck Solutions had the opportunity to drive the top of the range GMC Sierra HD Denali Ultimate. This is the top of the range model offered by General Motors for those looking to get a heavy-duty truck. It is one of the most luxurious trucks on the market, feeling more like a luxury vehicle than a work truck. 

While we drove the Ultimate trim, below we focus on all trim levels for the GMC Sierra HD, not simply the top end. 

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For 2024, GMC has redesigned the front bumper, fascia, and grille on all trim levels, changed wheel designs for some trims, added new colours, new 22-inch accessory wheels, new animated lighting, and rear wheelhouse liners as standard on Denali dual rear wheel (DRW) models.


The 2024 GMC Sierra HD is available with a choice of two engines, one gasoline and one diesel. The standard 6.6-liter V8 engine (gasoline or E85 FlexFuel) has 401 horsepower and 464 pounds/feet of torque on tap. The updated turbo diesel option is a Duramax 6.6L V8 with 470hp and a whopping 975 lbs/ft of torque. GM has improved the low-end torque by 25 percent, helping with towing. It also has improved the turbocharger, added new cylinder heads, new cylinder controller, new combustion system, and improved engine braking by using a more powerful turbo vane actuator and uprated valve springs.

Both are mated to a 10-speed automatic Allison transmission. The combination of the diesel engine and automatic transmission on the tester was great. For a large diesel engine, the vehicle was relatively quiet, and the shifting was always smooth. Power was more than enough for almost any job.


The main purpose of a heavy-duty pickup truck is to carry a lot of payload, and to tow as much as possible. While the GMC Sierra HD offers a plethora of model/trim options, the amount that you can tow or carry varies by trim level. For the 2500 level, the highest payload is on the 4WD regular cab with a diesel engine (3,850 lbs), with every other trim level starting at 3,381 lbs (2WD Crew Cab) and offering a payload in between the two extremes. The 3500 maxes out at 6,947 lbs on the 4WD (DRW), with all other models slotting in between 4,162 lbs and the max.

Conventional towing on 2500 and 3500 models goes between 14,500 and 20,000 pounds, with the highest amounts being available on the diesel engines. For those using fifth wheel/gooseneck for towing, the numbers range from 17,600 lbs to an amazing 36,000 lbs (on a 3500 2WD DRW with NHT package). All other trims fall somewhere in between the two ends of the spectrum.


The Sierra HD is available in 12 configurations (each available in 2WD or 4WD), so you can pick the one which is right as your work truck. The 2500 level is available in Regular Cab Long Bed, Double Cab Standard Bed, Double Cab Long Bed, Crew Cab Standard Bed, and Crew Cab Long Bed. The 3500 level comes in Regular Cab Long Bed single rear wheels (SRW), Regular Cab Long Bed (2WD & 4WD) DRW, Double Cab Long Bed SRW, Double Cab Long Bed DRW, Crew Cab Standard Bed SRW, Crew Cab Long Bed SRW, and Crew Cab Long Bed DRW.

Trim levels go from Pro (work truck), SLE, SLT, AT4, Denali, AT4X, and to Denali Ultimate.


Mario Cywinski is the editor of Modern WorkTruck Solutions and has worked in the automotive industry for nearly 20 years, both as an automotive journalist and working for a local dealership. He is a member of the Automobile Journalist Association of Canada and has been a judge for the Canadian Truck King Challenge. He can be reached at


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