Heavy-duty Sierra’s muscle-fix comes from a mix of new features, including a more powerful 6.6-liter Duramax turbo-diesel engine, and an all-new independent front suspension system that increases the front gross axle weight rating by up to 25%. Although a short-long arm/torsion bar front suspension remains a Sierra fixture, the 2011 truck has lighter and stronger forged steel upper control arms as well as machined cast iron lower control arms. Increased load capability is the byproduct of a new asymmetrical leaf-spring rear suspension. The stronger Sierra’s towing capability is 21,000 pounds while the heavy-duty vehicle’s payload capability is 6,635 pounds.

The new optional diesel engine releases 397 horsepower at 3000 rpm/765 pounds-feet of torque at 1600 rpm. This engine kicks out more power than the previous diesel, provides an up to 11% gain in highway fuel economy and reduces emissions by more than 60%. Mated to the improved Duramax diesel is the optional Allison 1000 six-speed automatic transmission. (Standard engine is the 6.0-liter Vortec gasoline V8 mated to a Hydra-Matic six-speed automatic transmission.) Sierra also gets longer wheelbases (133.6 inches to 167.7 inches) and wider front/rear tracks. Bending stiffness of the 11 all-new fully boxed frame assemblies increased more than 90% and beaming stiffness increased 20%. The Sierra 2500HD 4WD crew cab SLT carries a MSRP of $44,560.