The GMC Sierra HD is GMC’s heavy-duty pickup, offered as the three-quarter-ton 2500 HD and the one-ton 3500 HD in Regular Cab, Double Cab, and Crew Cab configurations. The 6.6L V8 gas engine is standard, and the Duramax 6.6L Turbo-Diesel V8 is available for the heaviest towing and standard on the Denali Ultimate. With seven trims from the work-focused Pro to the Denali Ultimate, the right truck depends on what you tow, what you haul, and how you drive every day. This guide covers the 2026 specs, trim differences, towing and payload information, and the questions we hear most from drivers in Saint Cloud, Kissimmee, and Poinciana. If your loads fit a lighter truck, compare it with the GMC Sierra 1500.
| Models | Sierra 2500 HD (three-quarter-ton) and Sierra 3500 HD (one-ton) |
|---|---|
| Engine options | 6.6L V8 gas: 401 hp, 464 lb-ft (standard) Duramax 6.6L Turbo-Diesel V8: 470 hp, 975 lb-ft (available; standard on Denali Ultimate) |
| Transmission | Allison 10-speed automatic |
| Cab styles | Regular Cab, Double Cab, Crew Cab |
| Bed lengths | Standard bed about 82 in; long bed about 98 in (by model and cab) |
| Seating | 3 in the Regular Cab; up to 6 in the Double Cab and Crew Cab |
| Max towing | 2500 HD: up to 22,390 lbs. 3500 HD: up to 36,000 lbs. Requires specific equipment. |
| Payload cited by GMC | 2500 HD: up to 4,049 lbs. 3500 HD: up to 7,290 lbs. Varies by configuration. |
| 2500 HD size | 79.8 in tall; 81.85 in wide without mirrors; Crew Cab 250.75 in (standard bed) to 266.77 in (long bed) long |
| Screens | 13.4-inch touchscreen and 12.3-inch driver information center (standard from the SLE) |
| Cameras | Up to 14 available camera views, including a transparent trailer view |
| Warranty | 3 yr/36,000 mi bumper-to-bumper; powertrain typically 5 yr/60,000 mi |
Specifications from GMC’s official Sierra HD page. Towing and payload figures are maximums for comparison and vary by configuration and equipment.
| Trim | Starting MSRP* | Highlights |
|---|---|---|
| Pro | $47,000 | Work-focused starting point with the 6.6L V8 gas engine, Allison 10-speed automatic, trailering package, trailering mirrors, and trailer brake controller. |
| SLE | $54,000 | Adds a 13.4-inch touchscreen, 12.3-inch driver information center, Traction Select System with Tow/Haul mode, and 17-inch machined aluminum wheels. |
| SLT | $65,200 | Adds heated power front seats with lumbar, a heated steering wheel, the ProGrade Trailering System with in-vehicle trailering app, and 18-inch wheels. |
| AT4 | $72,200 | Off-Road Suspension Package with Rancho shocks and skid plates, 20-inch gloss-black wheels, heated and ventilated leather seats, and Adaptive Cruise Control with trailering. |
| AT4X | $85,200 | Adds a 1.5-inch factory lift, Multimatic DSSV dampers, a rear electronic-locking differential, 35-inch mud-terrain tires, and 16-way massage seats. AT4X AEV Edition available. |
| Denali | $75,200 | 20-inch machined aluminum wheels, authentic wood trim, Forge perforated-leather seats, and 12-way heated and ventilated power front seats. |
| Denali Ultimate | $94,200 | Duramax turbo-diesel standard, Alpine Umber interior with full-grain leather, 16-way massage seats, 12-speaker Bose Premium Series audio, and illuminated power assist steps. |
*Starting MSRP as listed on gmc.com for the 2026 Sierra 2500 HD. The 3500 HD starts at $47,900. GMC’s MSRP excludes destination freight charge, tax, title, license, dealer fees, and optional equipment. The Duramax turbo-diesel is available on select trims.
The Pro is the work-focused starting point, with the 6.6L V8 gas engine, a trailering package, trailering mirrors, and a trailer brake controller as standard equipment. The SLE adds a 13.4-inch touchscreen, a 12.3-inch driver information center, and a Traction Select System with Tow/Haul mode. The SLT adds heated power front seats, a heated steering wheel, and the ProGrade Trailering System with an in-vehicle trailering app. The AT4 and AT4X bring off-road equipment to a heavy-duty truck, and the Denali and Denali Ultimate add luxury interiors, with the Duramax turbo-diesel standard on the Denali Ultimate. The trims table above lists starting MSRPs, and GMC describes each trim on its Sierra HD page.
GMC describes the 2500 HD as a three-quarter-ton truck that sits between the half-ton Sierra 1500 and the one-ton 3500 HD. The main difference is payload and towing capability: GMC lists available towing of up to 22,390 pounds for the 2500 HD and up to 36,000 pounds for the 3500 HD, so the 3500 HD is the one to look at for the heaviest trailers and loads. Starting MSRP is $47,000 for the 2500 HD and $47,900 for the 3500 HD, before destination freight, taxes, and fees.
GMC rates the 2026 Sierra 2500 HD to tow up to 22,390 pounds as a Regular Cab long bed 2WD with the available Duramax 6.6L Turbo-Diesel V8, the Max Trailering Package, the Gooseneck/Fifth-Wheel Prep Package, and a gooseneck or fifth-wheel hitch. The 3500 HD is rated up to 36,000 pounds as a Regular Cab long bed 2WD dual-rear-wheel model with the Duramax, the Max Trailering Package, a gooseneck hitch, the Convenience Package, and a 120-volt power outlet. Those are maximums intended for comparison, and the weight of passengers, cargo, and accessories reduces what you can pull. GMC publishes ratings by cab, engine, and drive in its trailering charts for the 2500 HD and the 3500 HD, and our team can confirm the rating for the exact truck you are considering.
The standard engine on the Sierra HD is a 6.6L V8 gas engine that makes 401 horsepower and 464 lb-ft of torque. The available Duramax 6.6L Turbo-Diesel V8 makes 470 horsepower and 975 lb-ft of torque with an Allison 10-speed automatic transmission, and it is standard on the Denali Ultimate. GMC ties its top towing ratings to the Duramax, so it is the choice if you tow near those limits, while the gas V8 is a strong fit for more moderate loads. GMC lists both engines on its engines page.
GMC’s Sierra HD page cites available payload of up to 4,049 pounds on the 2500 HD and up to 7,290 pounds on the 3500 HD, for comparison purposes. Your truck’s actual payload depends on the cab, bed, engine, drive, and options, and on whether a 3500 HD has single or dual rear wheels. Tongue or pin weight from a trailer counts against payload, so heavy towing and heavy bed loads work together. The label in the driver’s door jamb shows the exact figure for the truck you are looking at.
The Sierra HD is offered as a Regular Cab, Double Cab, and Crew Cab, with a standard bed of about 82 inches or a long bed of about 98 inches, depending on the model and cab. The Regular Cab seats three, and the Double Cab and Crew Cab seat up to six. For reference, GMC lists the 2500 HD Crew Cab at 250.75 inches long with the standard bed and 266.77 inches long with the long bed, and the 2500 HD is 79.8 inches tall and 81.85 inches wide without mirrors. The available MultiPro Tailgate combines six functions to make loading and unloading easier.
The ProGrade Trailering System helps streamline hitching and towing and is standard on the SLT with an in-vehicle trailering app. Adaptive Cruise Control with trailering accounts for the added drag and longer braking distances when towing. Up to 14 camera views are available depending on trim, including HD Surround Vision, a Bed View Camera, and an industry-first transparent trailer view. Driver assistance features do not replace the driver’s responsibility to operate the vehicle safely. GMC lists the equipment for the Pro, SLE, and SLT on its Sierra HD Pro, SLE, and SLT page.
Both bring off-road equipment to a heavy-duty truck. The AT4 has an Off-Road Suspension Package with twin-tube Rancho shocks and skid plates, exclusive 20-inch gloss-black wheels with available BFGoodrich off-road tires, and a Jet Black interior with Kalahari accents. The AT4X adds a factory-installed 1.5-inch suspension lift, Multimatic DSSV dampers, a rear electronic-locking differential, larger skid plates, and 35-inch Goodyear Territory mud-terrain tires. An AT4X AEV Edition with stamped steel bumpers and 18-inch Salta gloss-black wheels is also available. See GMC’s Sierra HD AT4 and AT4X page for details.
The Sierra 1500 is GMC’s half-ton light-duty pickup, with GMC listing towing of up to 13,300 pounds, and it is often the easier fit for daily driving and lighter work. The Sierra HD is built for heavier trailers and loads, with towing of up to 22,390 pounds on the 2500 HD and up to 36,000 pounds on the 3500 HD. If you regularly tow or carry loads near the limits of a half-ton truck, our team can help you compare the two side by side.
GMC’s new vehicle limited warranty includes bumper-to-bumper coverage for 3 years or 36,000 miles, whichever comes first. GMC lists typical powertrain coverage of 5 years or 60,000 miles and typical rust-through protection of 6 years or 100,000 miles, though other durations are available on some models. Confirm the terms that apply to the specific truck on GMC’s warranty page or ask our team.
Pricing for the 2026 Sierra HD starts at a $47,000 MSRP for the 2500 HD Pro and $47,900 for the 3500 HD, before destination freight, taxes, title, and fees, and it rises with trim, engine, and options. Current offers are listed on our new vehicle specials page. You can get pre-qualified with Capital One with no impact to your credit score, and value your trade online before you visit. Drivers from Kissimmee, Poinciana, and the rest of Osceola County can stop by our Saint Cloud store at 1001 E Highway 192, or reach the sales team at (321) 284-8127.
Ready to see one in person? Browse the new Sierra HD inventory above, or contact our team and we will help you compare trims and check availability.
