AT4’s Twin-Tube Rancho^®† shocks provide dampening when going off road, skid plates provide added protection for underbody components and Eaton^®† locking rear differential helps give you traction to handle rugged terrain.

• Standard 6.6L V8 Gas Engine with 6-Speed Automatic Transmission
  
  • 401 hp and 464 lb.-ft. of torque
    
• Available 6.6L Duramax^® Turbo-Diesel V8 Engine with Allison^®† 10-Speed Automatic Transmission
  
  • 445 hp and 910 lb.-ft. of torque
    
  • Large variable-speed cooling fan and dual path air induction system
    
  • Factory-installed diesel after-run function
    
  • Intelligent diesel exhaust brake system

The strong chassis and suspension are built upon a fully boxed, ladder-type frame built from high-strength steel using front hydroformed rails with clamshell design. The powerful frame and optimized body structure works in conjunction with large driveline components that feature high-strength axles and ring gears to bring immediate torque to ground for power while towing and off-roading.

To assist in clearing rugged terrain, available Sierra HD AT4 offers over 10 inches of ground clearance along with a maximum approach angle of nearly 27 degrees on select models.

The sturdy AT4 high clearance step is designed to help you and passengers get in and out of your vehicle. Textured surface helps provide increased traction and accessibility, even in wet and muddy conditions. Made to withstand harsh elements and environments.