The Sierra offers several models, each of which can be customized with similar features; payload capacity and luxury features differ.
The Sierra 1500, the 2500 Heavy Duty (HD) and the 3500 HD each come in four models. There's the basic work truck, the SLE, the SLT and the new Denali luxury trim, which was first introduced in 2011. Each of these models has different cab styles available as well, including a two-door cab, a four-door extended cab with small rear doors, or the crew cab with four full-sized doors. Each model also allows a choice of either bucket seats or a split bench. The extended and crew cabs feature bench seating for three passengers in the rear compartment and a flip-up cushion.
The available payload capacity on the Sierra series runs from half-ton to full-ton trucks. Each truck style comes with a 6.0-liter V8 gas engine that carries a 360 horsepower rating. The HD models have an optional Duramax 6.6-liter V8 diesel engine with 397 horsepower. Both engine types come with an Allison six-speed automatic transmission. Towing capacity ranges from 10,000 pounds up to a stunning 21,700 pounds for HD models.
Note: One source reports that all models but the Denali come with four-speed automatic transmission. It also states that some engines have displacement of less than 6.0 liters.
Mileage on the gas engine averages 13 mpg in the city and 16 mpg for highway use. Carrying a load or towing will reduce these amounts, although drivers can expect better mileage from the diesel engine. The diesel engine employs an exhaust-brake system, which provides slowing assistance on steep descents by capturing exhaust gases. The diesel engine is able to accommodate biodiesel 20.
The 2012 Sierra series comes with either rear-wheel drive or four-wheel drive. The four-wheel drive comes with options for either part-time application, which should not be used on dry pavement, or a full-time option that can be used anytime. Standard safety features include anti-lock brakes, emergency brake assist, stability and traction control, an antiskid system, side airbags in front, side-curtain airbags and daytime running lights.
Standard features vary by model, with the work truck offering basic additions such as air conditioning, music player, initial OnStar membership, cruise control and keyless entry. The SLE adds features such as alloy wheels and music controls on the steering wheel. The SLT ups the ante even more with rain-sensing wipers, a Bose music system with multi-disc CD changer, leather seats, remote engine startup and heated front seats. The Denali adds a heated steering wheel, special wheels and a navigation system.
Optional equipment on the 2012 Sierra series includes touchscreen navigation, power-adjusted pedals, EZ-Lift tailgate assistance, bed extender, cargo rails with sliding anchors, and an off-road package with chassis skid plates and upgraded suspension. Other possible luxury additions include heated front seats and a DVD player for rear-seat viewing.