​​2026 GMC Sierra HD​

Performance

The standard engine for the 2026 Sierra HD is the 6.6-liter V-8 gasoline engine. It offers 401 horsepower and 464 pound-feet of torque. Available is the Duramax 6.6-liter V8 turbodiesel with 470 horsepower and a peak torque of 975 pound-feet. Torque is up 25% at lower rpm for improved climbing and trailering ability. 

The Allison 10-speed transmission is standard on all engines. With far more ratios in a similar overall range, the engine stays closer to its peak torque range, putting every single pound-foot of torque to good use. This increases the gas engine’s maximum towing capacity by 2,000 pounds for a total of 26,000 pounds. In addition, ratio changes are smoother, and downshifts are quicker. 

Regarding capabilities, the 2026 Sierra 2500HD can tow up to 22,500 pounds, while the 3500HD has a maximum tow rating of 36,000 pounds using a gooseneck or fifth-wheel connection. Conventional towing is available up to 20,000 pounds for both the 2500HD and 3500HD. Payloads can go up to 3,759 pounds for the 2500HD and 7,290 pounds for the 3500HD. 

Exterior

Last year, GMC gave the Sierra HD a styling overhaul that included a new front bumper, fascia, and grille. Each trim gets a unique look, and animated light signatures are available. The SLE, AT4, and Denali trims get new wheel designs, and dual-rear-wheel models get 18-inch polished aluminum wheels. The range-topping Denali Ultimate gets exclusive badges and 20-inch wheels, with plenty of exterior chrome accents. 

Interior

Each trim gets a unique interior design, with refreshed styling and features across the Sierra lineup. GMC offers a variety of colors and materials, and the top trims get soft leather upholstery and accent stitching. The Sierra HD Denali Ultimate offers full-grain leather upholstery with an Ultimate badge on the seatbacks. The door panels feature full-grain leather, and the front seats offer 16-way adjustability with a massaging function. GMC also equips a microsuede headliner, a power sunroof, and etched stainless steel speaker grilles in the top trim.

Technology

GMC provides a 7.0-inch touchscreen with Apple CarPlay and Android Auto as standard, along with six speakers, a 3.5-inch gauge cluster display, USB ports, and a Wi-Fi hotspot. Most trims get a 12.3-inch digital gauge cluster and a bright 13.4-inch touchscreen. The system includes seven speakers, SiriusXM radio, remote start, dual-zone climate controls, and an available universal garage door opener. Top trims add a 12-speaker Bose audio system and a 15.0-inch head-up display. GMC’s infotainment software benefits greatly from the addition of Google Built-in, which brings Maps, Google Assistant, and other features.

GMC offers the most available trailering assistance technologies in its class through GMC’s ProGrade trailering system, offering up to 14 camera views, including “transparent” trailer views, extended blind spot monitoring, trailer length indicators, and more.  

Safety

Heavy-duty trucks don’t get the crash testing that light-duty trucks do, but GMC equips a solid list of standard driver aids. Forward collision warnings, automatic emergency braking, automatic high beams, lane departure alerts, pedestrian detection, a rearview camera, buckle-to-drive, and a teen driver mode come standard. Available tech includes adaptive cruise control, blind spot monitoring with rear cross-traffic alerts, parking sensors, a surround-view camera system, and more.