Key Features of the 2026 GMC Sierra 3500 HD

Duramax 6.6L Turbo-Diesel V8

The heart of the heavy-duty lineup is the Duramax 6.6L Turbo-Diesel V8, tuned for 470 horsepower and an immense 975 lb-ft of torque. That mountain of low-end twist builds early and stays consistent, giving you assertive launches with loaded trailers and confident uphill pulls without the need for constant downshifts. The 10-speed automatic transmission is calibrated to make the most of the Duramax’s torque band, delivering crisp, decisive gear changes that help maintain momentum and cooling under sustained grades. For drivers who tow regularly—especially with larger fifth-wheel or gooseneck trailers—the Duramax is a standout choice for both strength and refinement. It feels settled at speed, pairs naturally with the 3500 HD’s available dual rear wheel configuration, and brings a sense of control that helps you stay relaxed on demanding routes.

6.6L Gas V-8 with 10-Speed Automatic

The standard 6.6L gas V-8 is a durable workhorse rated at 401 horsepower and 464 lb-ft of torque. It offers steady performance, predictable throttle response, and a clean, linear power curve that’s well suited for mixed-duty owners who combine weekday hauling with weekend towing. The 10-speed automatic complements the gas V-8 with close ratios and smart shift logic that keep the engine in the sweet spot under varying loads. If your typical use case includes job-site materials, equipment, or a moderately sized trailer, the gas V-8 delivers stout capability while keeping ownership straightforward. It is a confident match for drivers who want heavy-duty strength without stepping into diesel torque, and it maintains the Sierra HD’s composed ride and reassuring braking feel when properly equipped.

Dual Rear Wheel Capability and Max Trailering

To unlock the Sierra 3500 HD’s most impressive towing numbers, select the dual rear wheel (DRW) configuration. The additional tire contact patch and wider rear track provide greater lateral stability under high tongue or pin weight, especially at highway speeds and on uneven surfaces. Properly configured, a DRW 3500 HD can tow up to 36,000 pounds with a gooseneck hitch and up to 32,000 pounds with a fifth-wheel setup. Together with the available 4WD system and the 10-speed automatic, the DRW model maximizes traction as loads increase and conditions vary. Whether you haul heavy construction equipment or a large fifth-wheel RV, the DRW option helps your Sierra stay settled and communicative, transforming major towing tasks into predictable routines you can trust day after day.

MultiPro Tailgate

GMC’s MultiPro Tailgate adds a six-function solution that gives you better access, smarter loading, and practical on-site flexibility. Use the primary gate for standard bed access, or fold the inner gate to form a convenient, lower reach point for loading and unloading. The inner gate can also transform into a full-width step that makes it easy to get into the bed—especially valuable on lifted or heavy-duty trucks. When cargo needs containment, the inner gate’s load stop helps secure longer materials, and the work surface configuration creates a stable platform for a laptop or paperwork. Pair MultiPro with available bed lighting, movable tie-downs, and an in-bed 120-volt outlet to turn the Sierra 3500 HD’s box into a mobile job station where tools, fasteners, and equipment are always at hand.

13.4-inch Touchscreen with Google Built-in

Higher trims of the Sierra HD offer a command center built around a 13.4-inch diagonal touchscreen featuring Google Built-in. The large display consolidates navigation, media, and vehicle settings with clear graphics and responsive controls designed for use with work gloves. Use Google Assistant for voice-driven directions, reminders, or quick calls while keeping your hands on the wheel. Wireless Apple CarPlay and Android Auto are supported across the lineup, so your familiar apps are ready without cables. Many configurations also add a 12.3-inch digital gauge cluster that can prioritize towing data, turn-by-turn directions, or driver information at a glance. The result is a tech suite that feels genuinely helpful—particularly when you are juggling routes, loads, and schedules.