The 2008 GMC Sierra lineup consists of the 1500, 2500HD, 3500HD, and the luxurious Denali. The 1500 is the half-ton pickup suitable for personal use, while the Denali gets its own 403-horsepower 6.2L aluminum V8 engine. In between lie the trucks designed for work upon which GMC has made their "Professional Grade" reputation. Like many pickups today the 2500/3500HDs are available in a wide variety of configurations, all of which are available with either two- or four-wheel drive.
The Sierra 2500HD allows a combined passenger/cargo weight of nearly 4,000 pounds depending on cab type, bed length, and drivetrain, while the 3500HD can handle up to 5,300 pounds when configured with dual rear wheels. This is the optimum selection to take advantage of the 3500HD's 13,000-pound towing capacity.
All GMC Sierras have a very appealing interior, with handles and knobs designed to be operated while wearing work gloves. Under-seat storage enhances utility, as does a cavernous double glove box.
Three cab styles are available (regular, extended, and crew cab) and three box configurations are available (standard, long, and Dually long). The extended cab has two rear-hinged, half doors that open 170 degrees and have fully opening windows. Crew cab models have four full-size doors and space for six adults. Both the extended cab and crew cab have a rear seat bottom that handily folds up out of the way without the need of a release lever.
3500HD models come in two additional variants, identified by SRW (single rear wheels) or DRW (Dual rear wheels, sometimes called Dually). The DRW models offer enhanced stability for those who routinely tow trailers near the upper end of capacity.
Most folks will get by just fine with the standard 6.0L gas V8 engine that uses variable valve timing to produce 353-horsepower and 373 ft-lbs of torque. It is backed up by the latest version of General Motors' Hydra-Matic transmission, now with six speeds.
For those who need maximum grunt, a 6.6L diesel engine makes only slightly more horsepower (365), but its 660 ft-lbs of torque should be capable of doing just about any job. This torque-monster is backed up by a six-speed Allison automatic transmission.
Two suspensions are offered on the HD trucks. In addition to a standard suspension, the optional Z71 suspension is aimed towards off-road use and includes skid plates along with other additional equipment.
GMC's HD series has a bold appearance, especially in front, with a wider grille, domed hood, and broader fenders. The HD trucks boast a ladder frame, a hydroformed front section, a structure designed for better crash protection, recirculating-ball steering gear aimed at improving steering feel, and a strong four-wheel disc brake system with anti-lock. The brakes feature an integrated trailer brake controller.
Trims run the range in price and comfort. The WT (Work Truck) comes with an interior designed to stand up to rough duty. The SLE1 adds such niceties as cruise control, a CD player, power door locks, and a leather-wrapped steering wheel. The SLE2 upgrades to dual-zone climate control, six-way power seat controls, and steering-wheel mounted audio controls. Finally, the SLT adds a premium leather interior, 17-inch bright machined aluminum wheels, a six-disc CD changer, and even heated windshield wiper fluid.
Some of the more notable options include power-adjustable pedals, Ultrasonic Rear Parking Assist, a remote starting system, a rear-seat DVD entertainment system on crew cabs, an EZ Lift tailgate, and a power-sliding rear window on extended and crew cabs. A wide range of audio systems includes MP3- and DVD-compatible players.
The GMC Sierra 2500HD and 3500HD, one year off of a complete redesign, get XM satellite radio standard for 2008, and Dark Crimson and Sonoma Red metallic paints replace Sport Red on the color palate. Universal home remote is now an option on the uplevel SLT models, rather than being standard equipment. Dual-rear wheel 3500HD models now ride on 17-inch wheels instead of 16-inchers.