2026 GMC Sierra 2500

The 2026 GMC Sierra 2500HD AT4 4WD Crew Cab (159" Bed) is engineered for extreme capability with premium refinement. Finished in Onyx Black with a rugged yet upscale Jet Black interior accented by Kalahari highlights, this heavy-duty AT4 delivers uncompromising diesel power, advanced trailering technology, and bold off-road presence.

Performance & Capability

At the heart of this Sierra HD is one of the most respected diesel powerplants in the segment, delivering immense torque for towing and hauling.

• Duramax 6.6L Turbo-Diesel V8 (B20 Diesel Compatible)

  • 470 horsepower @ 2,800 rpm

  • 975 lb-ft of torque @ 1,600 rpm

  • Includes engine block heater

• 10-Speed Automatic Transmission

• Two-Speed Active Transfer Case with electronic Autotrac

• Integrated Trailer Brake Controller

• Trailering Information Label with conventional, gooseneck & 5th-wheel ratings

Exterior & AT4 Design

Purpose-built with off-road styling cues and functional enhancements.

• Onyx Black Exterior Finish

• 20" High-Gloss Black Aluminum Wheels (8-Spoke)

• LT275/65R20 All-Terrain Tires

• Rear Wheelhouse Liners

• Power-Retractable Black Assist Steps with LED Lighting

• Animated LED Signature Tail Lamps

• GMC MultiPro Tailgate with six functional load/access features

• EZ Lift Tailgate with power lock, release & hitch area lighting

• Bed rail and tailgate protection caps

Interior & Technology

The AT4 cabin blends durability with modern connectivity and comfort.

• Jet Black Interior with Kalahari Accents

• Wireless Apple CarPlay & Android Auto

• Wireless Phone Charging

• Wi-Fi Hotspot Capability

• Multiple USB Charge/Data Ports (front & rear)

• Power Windows with Driver & Passenger Express Up/Down

• Rear Power Window with Express Down

Trailering, Safety & Driver Assistance

Designed to inspire confidence whether towing or navigating challenging terrain.

• Trailer Side Blind Zone Alert

• Trailer Camera Provisions with advanced trailer viewing software

• Tire Pressure Monitoring System with Tire Fill Alert

• Theft-Deterrent System with Engine Immobilizer

• Teen Driver Technology with in-vehicle report card

Summary

The 2026 GMC Sierra 2500HD AT4 is the ultimate heavy-duty truck for drivers who demand diesel strength, off-road capability, and premium technology in one commanding package. With its Duramax turbo-diesel power, advanced trailering systems, and distinctive AT4 styling, this Sierra is built to handle the toughest jobs while delivering everyday refinement.

ENGINE, DURAMAX 6.6L TURBO-DIESEL V8, B20-DIESEL COMPATIBLE (470 hp [350.5 kW] @ 2800 rpm, 975 lb-ft of torque [1322 Nm] @ 1600 rpm) (Includes (K05) engine block heater.), ASSIST STEPS, POWER RETRACTABLE, BLACK includes LED lighting, Wireless phone projection for Apple CarPlay and Android Auto, Wireless Charging, Wipers, front rain-sensing, Windows, power rear, express down, Windows, power front, drivers express up/down, Window, power front, passenger express up/down, Wi-Fi Hotspot capable (Terms and limitations apply. See onstar.com or dealer for details.), Whee