The 2008 GMC Sierra 3500HD Dually 4WD is a carryover from the prior model year. Nevertheless, the full-size pickup still maintains the same generous power, classic American styling, and wealth of options. Dually refers to the rear quad tires that provide a more stable ride for handling large loads and towing. Often used as a work truck, the 2008 GMC Sierra 3500HD has a towing capacity of up to 13,000-lbs and can haul loads up to 5,127-lbs, giving the model top capacities in its category.

Under the hood, the GMC Sierra 3500HD Dually is available with either a Vortec 6.0L Variable Valve Timing SFI V8 or a Duramax 6.6L Turbo Diesel V8. The Turbo Diesel model can be equipped with bio-diesel fuel capabilities as well, which both saves buyers money at the pump and emits fewer pollutants into the environment. Variable Valve Timing refers to a program that allows the engine to adjust the height of lift, the duration, and timing of the intake and exhaust valves. This allows the vehicle to conserve fuel and also provide a boost of power when needed.

Two automatic transmission options are available for buyers to choose from. The standard heavy duty six-speed automatic includes a tow/haul mode, and the Allison 1000 six-speed automatic features electronic engine grade braking. However, the Allison transmission is only compatible with the Turbo Diesel engine model.

A number of standard and optional features are offered on the 2008 Dually 4WD. Some standard features include cruise control, a one-year subscription to the OnStar program, two auxiliary power outlets, a tire pressure monitoring system, and an MP3-compatible CD player. Buyers can upgrade to options like a premium sound system with DVD player, navigation unit, sunroof, remote start system, and rear parking assist. The rear parking assist is a program that allows drivers to see what is behind the vehicle on an LED screen located on the dash. An alert will sound if there is an object blocking the Sierra 3500HD's rear path as well.

Unfortunately, the 2008 GMC Sierra 3500HD Dually 4WD does not have an EPA estimated fuel rating. Intro priced at around $25,515, the GMC Sierra 3500HD is comparable with the competition; however, buyers that are looking for a more contemporary exterior design might want to take a look at Dodge or Ford's options.