The 2026 GMC Sierra 3500 HD is engineered to impress where it counts most - at work. The available Duramax 6.6-liter turbo-diesel V8 engine produces up to 470 horsepower and 975 pound-feet of torque, giving you the pulling power to handle demanding hauls with confidence. Paired with an Allison 10-speed automatic transmission, this powertrain delivers smooth, efficient power transfer whether you're climbing grades or navigating job sites. A standard 6.6-liter V8 gasoline engine is also available for those who prefer a proven workhorse setup.

Step inside the 2026 Sierra 3500 HD and you'll find a cab designed with both the driver and crew in mind. Available seating configurations include Regular Cab, Double Cab, and Crew Cab options, giving you the flexibility to fit your lifestyle and workload. Upper trims offer available leather-appointed seating, genuine open-pore wood trim, and premium heated and ventilated front seats. The Multi-Flex tailgate - available on select configurations - adds clever functionality that makes loading and unloading faster and easier. Thoughtful storage solutions and generous legroom round out an interior built for long days on the road.

The 2026 Sierra 3500 HD keeps you connected and in control with a suite of modern technology features. An available 13.4-inch diagonal HD touchscreen runs Google built-in, providing seamless access to Google Maps, Google Assistant, and compatible apps. Available Super Cruise - GMC's hands-free driver-assistance technology - allows for hands-free driving on compatible roads. Wireless Apple CarPlay and wireless Android Auto come available to keep your devices integrated without the clutter of cords. Available Pro Grade trailering tools, including an in-vehicle Trailering App and up to 15 available camera views, make hitching up and managing your trailer simpler than ever.

GMC equips the 2026 Sierra 3500 HD with a comprehensive set of safety and driver-assistance technologies designed to protect you and your load. Available features include Forward Collision Alert, Automatic Emergency Braking, Lane Keep Assist with Lane Departure Warning, and Rear Cross Traffic Alert. The available HD Surround Vision system gives you a bird's-eye view of your surroundings, which is especially valuable when maneuvering in tight spaces or backing into a loading area. OnStar safety and security services are also available to provide added peace of mind on every drive.

The 2026 GMC Sierra 3500 HD is offered in a well-structured range of trim levels to match every driver's needs and budget. The lineup includes the Pro, SLE, SLT, AT4, Denali, and Denali Ultimate. The entry-level Pro delivers capable work-truck fundamentals, while the SLE and SLT add comfort and technology upgrades. The AT4 trim brings serious off-road credentials, including an available front locking differential and skid plates. At the top of the range, the Denali and Denali Ultimate trims offer the finest combination of luxury and performance, featuring exclusive interior appointments and premium exterior details that set the truck apart.

Whether you're searching for a capable work vehicle or a refined heavy-duty truck that doubles as a daily driver, drivers in Gillette, WY will find a Sierra 3500 HD configuration that fits the bill perfectly.