What Changed for 2008:
- Available 22-inch wheels
- XM satellite radio becomes standard
- Power-adjustable driver's seat available with regular cab's bench seat
- New Sierra All-Terrain model
- Integrated trailer-brake controller added
GMC has been building trucks since 1902, and the Sierra was most recently updated for the 2007 model year. The light-duty, half-ton Sierra shares its design with the Chevrolet Silverado. It comes in a plethora of combinations. Body styles include regular cab, extended cab, and crew cab configurations. Regular cabs have two doors and seat 3 with a front bench seat. Extended cabs and crew cabs have four doors and seat 6 with a folding second-row bench seat; it is split in crew cabs and a split rear seat is optional in extended cabs. The extended cab's rear doors are hinged at the rear and don't open independently of the front doors. The crew cab has full-size rear doors. Three cargo-box lengths are available. Regular and extended cabs offer 6-foot, 6-inch or 8-foot beds; crew cabs have a 5-foot, 8-inch bed. Buyers can choose between rear-wheel drive (RWD) and 4-wheel drive (4WD) for all models but the Denali, which offers RWD or all-wheel drive (AWD). A Sierra Hybrid model will be added for the 2009 model year.
The 2008 GMC Sierra is offered in six trim levels: Work, SL, SLE1, SLE2, SLT, and top-of-the-line Denali. Sierras offer \"pure pickup\" and \"luxury-inspired\" interior designs. Work, SL and SLE models have the pure pickup design with larger controls, a double glovebox, a fold-down armrest storage console, and a lockable underseat center storage bin with a power outlet. SLT and Denali models have the luxury-inspired design with smaller controls, bucket seats with a center console, a single glove box, and more upscale trim.
Standard equipment on Work includes a tilt steering wheel, vinyl upholstery, front split-bench seat, OnStar with one year of service, AM/FM/CD player, XM satellite radio, automatic headlights, vinyl floor covering, theft-deterrent system, and P245/70R17 tires on steel wheels. Extended and crew cabs also get air conditioning. In addition, crew cabs have power locks and remote keyless entry, while 4WD models add tow hooks and P265/70R17 tires. The SL trim adds cruise control, cloth upholstery, driver-seat lumbar adjustment, heated power mirrors, carpeting, floor mats, and chromed steel wheels. The SLE1 trim has air conditioning, leather-wrapped steering wheel, power windows and locks, remote keyless entry, auto-dimming rearview mirror, fog lights, tow hooks, and the Z85 handling/trailering suspension. Standard on the SLE2 are dual-zone automatic climate control, 6-way power front bucket seats, center console, steering wheel audio controls, and aluminum wheels. The SLT trim has leather upholstery, heated 12-way power front seats, driver-seat memory, driver's side auto-dimming exterior mirror, and Bose speakers with a subwoofer. The Denali has a locking rear differential, power-adjustable pedals, 6-disc CD changer, universal garage door opener, remote engine starting, a trailer tow package, skid plates, sport suspension, and P265/65R18 tires.
Due later in the model year is the Sierra All-Terrain, which will be offered with extended cab standard box and crew cab models in either RWD or 4WD. It will feature GM's Z71 off-road suspension, skid plates, locking rear differential, heavy-duty trailering package, 18-inch chrome wheels, Rancho Tenneco shocks, a specific instrument panel with brushed metal appearance, and an available exclusive 2-tone leather seat color combination.
Options on the 2008 GMC Sierra 1500 pickups include many of the Denali's standard features, as well as a cargo management system, power-sliding rear window, roof rack, navigation system, sunroof, and a rear DVD entertainment system.
Five engines are offered on the 2008 GMC Sierra 1500. The base 4.3-liter V-6 engine makes 195 hp and 260 lb.-ft. of torque. It is only offered for Work models. Work and SL models are offered with a 4.8-liter V-8 engine that produces 295 hp and 305 lb.-ft. of torque. All models but the Denali are available with a 5.3-liter V-8 engine that cranks out 315 hp and 338 lb.-ft. of torque. The 5.3-liter engine is available as a FlexFuel engine that can run on regular gasoline or E85, a blend of 85 percent ethanol and 15 percent gasoline. SLE1, SLE2, SLT, and All-Terrain models can be ordered with a 6.0-liter V-8 engine that delivers 367 hp and 375 lb.-ft. of torque. Both the 5.3- and 6.0-liter V-8 engines have GM's Active Fuel Management system that shuts down four cylinders under light load conditions to conserve fuel. The top-line Denali has a 6.2-liter V-8 engine that puts out 403 hp and 415 lb.-ft. of torque. All Sierras have a 4-speed automatic transmission, except the Denali, which has a 6-speed automatic transmission.
EPA fuel economy ratings range from 15 mpg city/20 mpg highway for a RWD Sierra with either the 4.3-liter V-6 engine or the 5.3-liter V-8 engine to 14 mpg city/19 mpg highway for a RWD model with the 4.8-liter V-8 engine and 13 mpg city/17 mpg highway for a 4WD 6.0-liter V-8 engine Sierra to 12 mpg city/18 mpg highway for the AWD Denali.
The standard 4WD setup is a part-time system that should not be left engaged on dry pavement and has low-range gearing. SLE, SLT and All-Terrain models have GM's AutoTrac 4WD, which can be left engaged on dry pavement and includes low-range gearing. The Denali has a standard locking rear differential and can be ordered with full-time AWD that lacks low-range gearing.
The 2008 GMC Sierra 1500 rides on GM's GMT900 full-size truck platform that features a fully-boxed, hydro-formed frame. Properly equipped, a half-ton Sierra 1500 can tow up to 10,500 pounds and haul a maximum payload of 1947 pounds.
Standard safety equipment on the 2008 GMC Sierra 1500 includes dual-stage front air bags, anti-lock brakes, and a tire-pressure monitor. Traction control and electronic stability control are standard on crew cabs and optional on extended cabs with the short bed. Head-protecting curtain side air bags with rollover deployment and rear obstacle detection are standard on Denali and optional otherwise. A rearview camera is also optional.
In crash tests conducted by the National Highway Traffic Safety Administration (NHTSA), the half-ton GMC Sierra has received a 5-star front-impact rating for the driver and front passenger, a 5-star rating for front and rear occupants in side impacts, and a 4-star rollover-resistance rating.
An integrated trailer-brake controller is available on extended cab and crew cab models. It is located on the instrument panel and precludes the need for external or aftermarket brake control systems. The trailer-brake controller is integrated with the ABS system and provides immediate and measured brake force signaling to electric-controlled trailer brake systems, the automaker says.