Key Features of the 2026 GMC

Duramax 6.6L Turbo-Diesel V8

For drivers who tow frequently, the Duramax 6.6-liter turbo-diesel V-8 is the heart of the heavy-duty lineup. Rated at 470 horsepower and a massive 975 lb-ft of torque, it serves up confident, low-rpm thrust that translates to steady merges, assured passing, and composed climbs with a loaded trailer. Matched to a 10-speed automatic, the Duramax feeds torque with precision to help minimize hunting between gears on long grades and maintain smooth progress on rolling terrain. The powerplant’s refinement is as notable as its strength — diesel clatter is well-controlled, and vibration is impressively contained for a truck of this capability. If your daily routine includes fifth-wheel or gooseneck duties, the diesel’s effortless torque makes the 2026 GMC Sierra 2500 HD an easy recommendation.

6.6L Gas V-8

The standard 6.6-liter gas V-8 delivers 401 horsepower and 464 lb-ft of torque, making it a confident partner for mixed-use owners who split time between commuting, job sites, and recreational towing. This engine’s clean throttle response and predictable power curve shine in stop-and-go traffic, on two-lane backroads, and when hitching up a moderate trailer. It is also paired with the 10-speed automatic, which helps maximize usable torque and keep revs in a comfortable range. For many buyers, the gas V-8 strikes an appealing balance of simplicity and everyday strength, backed by GMC’s reputation for durability in the heavy-duty segment.

10-Speed Automatic Transmission

Both Sierra HD engines are paired with a 10-speed automatic that elevates drivability and control. With more ratios to work with, the transmission can hold an optimal gear on climbs, downshift decisively for passing, and reduce engine strain when cruising. The calibration is crisp and unobtrusive — a benefit you notice most when the truck is loaded and conditions change quickly. Towing confidence comes from predictable gear selection and smooth torque delivery; daily drivability benefits from reduced shift shock and a more relaxed engine note on the highway. It is the kind of refinement that makes a heavy-duty truck feel less taxing over long days behind the wheel.

MultiPro™ Tailgate

GMC’s MultiPro™ tailgate is a practical standout on the 2026 lineup. With six functions built into one smart design, it transforms the box into a flexible workstation: lower the inner gate for a second-tier load stop, fold it into a step for easier bed access, or create a convenient surface for securing tools and laptops. Paired with available bed lighting, movable tie-downs, and a 120-volt outlet, the tailgate and cargo box work together to speed up loading, secure odd-shaped items, and reduce strain when climbing in and out. For owners who load up daily — from landscaping equipment to construction materials to weekend toys — this multipurpose solution quickly becomes a favorite capability enhancer.

13.4-Inch Touchscreen With Google Built-in

Upper trims of the Sierra HD deliver a tech-forward cabin anchored by an available 13.4-inch touchscreen with Google Built-in. This system brings Google Assistant, Google Maps, and select Google Play apps directly into the dashboard for natural voice control, intuitive navigation, and familiar functionality. Wireless Apple CarPlay and Android Auto are supported across the lineup, and many configurations add a 12.3-inch digital gauge cluster to keep key vehicle and towing data in view. The result is a cockpit that feels modern, reduces clutter from device cables, and supports long-haul productivity — exactly what busy owners need when trailering to job sites or heading out on multi-state trips.