The Sierra HD arrives in three cabs (regular, extended, crew) and two weight classes, 2500 HD and 3500 HD, all with 2WD or 4WD. The 2500 (sometimes called 3/4-ton) offers two pickup box sizes, while the 3500 (1-ton) is eight-foot box only; dually versions are scheduled for May 2007. If you wish to add your own utility box or flatbed, cab and chassis models are offered.

GMC nomenclature labels trim levels as commercial-grade Work Truck, popular SLE (1 and 2), and premium SLT that resembles a Yukon sport-utility up front.

Basic WT fare includes a split vinyl bench seat (and split rear on long cabs), stereo radio, air conditioning, six-speed automatic transmission, tire pressure monitors, and ABS.

Mid-level SLE models include all basic equipment and add cruise control, chromed steel wheels, electronic shift for 4WD, auto-dimming mirror and compass, driver lumbar, locking seat cushion storage, and leather-wrapped steering wheel. The SLE 2 package adds fog lamps and interior upgrades such as cloth-upholstered power-adjustable front seats and redundant controls on the steering wheel.

SLT badges are reserved for the priciest Sierras, those with an interior modeled after GMC luxury utilities. These include as standard leather upholstery with 12-way power and heated front seats, two-person driver memory, heated windshield washer fluid system, locking differential, remote start, towing package, 17-inch aluminum wheels, and a Bose audio system with subwoofer.

Base power for all GMC HDs is the latest 6-liter V-8 with an iron block for durability and variable valve timing for efficiency; it rates 353 hp and 375 lb-ft of torque (312 hp for GVWR above 10,000 pounds). The sole option is a 6.6-liter Duramax turbodiesel, nominally more powerful than last year's diesel at 365 horses and 660 lb-ft of torque. A six-speed automatic is the only transmission offered, and on diesels it adds $1,200 to the engine's roughly $7,200 tab; the big 8.1-liter gas engine has also been dropped.

Sierras can be set up for anything from a night on the town, moonroof, satellite radio, navigation, to a year on the ranch or fleet garage with snow plow prep, integral trailer brake control, remote start, and power takeoffs. Determining exactly the right model and options will take careful and honest shopping because of the sheer number of choices.

Safety equipment includes frontal airbags, front seat belt pretensioners (a first for HD pickups), ABS, and OnStar.

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