2026 GMC Sierra 3500 Riverton WY

The 2026 GMC Sierra 3500 HD offers two powertrains built to handle heavy loads and steep mountain grades. The standard 6.6L V8 gas engine produces 401 horsepower and 464 lb-ft of torque, supplying immediate throttle response for everyday hauling. Drivers seeking maximum low-end pulling power can select the available Duramax 6.6L Turbo-Diesel V8 engine, which generates 470 horsepower and 975 lb-ft of torque. Both engines pair with an Allison 10-speed automatic transmission that optimizes power delivery during gear shifts, reducing transmission strain when climbing or descending steep elevation changes along Highway 26 and Highway 789. Standard Tow/Haul mode and Auto Grade Braking automatically adjust shift schedules to help control vehicle speeds on long downhill stretches without overusing service brakes.

Single rear wheel and dual rear wheel setups allow you to match the truck to your specific trailering demands. When properly equipped, maximum towing capacity reaches up to 36,000 lbs on dual rear wheel models fitted with the available Duramax 6.6L Turbo-Diesel V8 and gooseneck or fifth-wheel hitch setup. Payload capacity reaches up to 7,290 lbs when properly equipped, supplying capacity for tools, equipment, or building supplies in the bed.

The exterior design of the Sierra 3500 HD blends practical functionality with signature GMC styling. Distinctive grille designs mark each trim, while standard C-shaped LED projector headlamps feature animated lighting sequences on select models. Outside power-adjustable vertical trailering mirrors feature power folding and extending capabilities with auto-dimming upper glass to maintain visibility when hauling wide loads. High-strength roll-formed steel forms the bed, yielding maximum cargo bed volume for supplies. The available GMC MultiPro Tailgate adds six distinct positions, functioning as a load stop, full-width step, or mobile work surface. Owners can also add a factory spray-on bedliner to protect the bed surface from heavy gear and tools.

Inside the cab, the 2026 GMC Sierra 3500 HD provides generous front legroom and headroom across Regular Cab, Double Cab, and Crew Cab configurations. Work-focused models include a 40/20/40 split-bench front seat with under-seat storage, while upper trims offer heated and ventilated front leather bucket seats. Storage compartments throughout the cab offer space for storing tie-downs and job site equipment. Available 16-way power-adjustable front seats feature integrated massage functions, while real Paldao wood accents and full-grain leather seating elevate the interior environment on top-tier trims.

Modern technology simplifies trailering and daily driving across central Wyoming. An available 13.4-inch diagonal GMC Premium Infotainment System integrates Google built-in alongside wireless Apple CarPlay® and wireless Android Auto™ compatibility. Drivers can view vital vehicle diagnostics on an available 12.3-inch diagonal digital Driver Information Center or project key information onto the windshield using an available 15-inch Head-Up Display. Up to 14 available camera views, including Bed View and Transparent Trailer View, make hitching and maneuvering large trailers straightforward. The ProGrade Trailering System includes an In-Vehicle Trailering App that supports pre-departure checklists, trailer tire pressure monitoring, and light diagnostic routines.

Pro: Serving as the functional foundation of the lineup, the Pro trim comes standard with the 6.6L V8 gas engine, Allison 10-speed transmission, Trailering Package, vertical trailering mirrors, and wireless smartphone compatibility. SLE: Building on the core features, the SLE adds the 13.4-inch infotainment display, 12.3-inch digital driver cluster, and power equipment, along with availability of the X31 Off-Road Package. SLT: Upgrading to the SLT brings heated 10-way power leather front seats, dual-zone climate control, the ProGrade Trailering System, and available MultiPro Tailgate access. AT4 & AT4X: Designed for off-road job sites and trail access, the AT4 features an off-road suspension with twin-tube Rancho shocks, skid plates, red recovery hooks, and 4WD. The AT4X enhances capability with Multimatic DSSV dampers, a rear e-locking differential, and 35-inch Goodyear Territory MT tires. Denali: The Denali trim introduces signature chrome exterior accents, 20-inch ultra-bright machined aluminum wheels, Forge perforated leather seating, authentic wood trim, and a 12-speaker Bose Premium Sound System. Denali Ultimate: The flagship Denali Ultimate comes standard with the Duramax 6.6L Turbo-Diesel V8, Vader Chrome exterior accents, 20-inch ultra-bright wheels with gloss-black inserts, Alpine Umber full-grain leather, and 16-way power massaging front seats.