Introduction

The GMC Sierra was redesigned from the ground up last year, using proven powertrains, so the 2008 model year brings minor refinements, a few additions, and a special All-Terrain model. The Sierra is built on a stiff platform for a smooth ride and sharp handling. The GMC Sierra shares platforms with the Chevy Silverado but its exterior styling is quite different. Sierra interiors offer a choice of two dashboard styles. The 2008 GMC Sierra is offered in a Denali version, which makes for a comfortable, luxurious, pickup with the emphasis on performance rather than payload and towing capacity. The Sierra Denali offers the same sort of higher-line content as GMC's upscale Yukon Denali sport utility. Amongst the various cab styles, bed lengths, and eight engine choices (of five sizes) the Sierra offers many permutations. There are limitations however, such as the biggest engine is limited to the Denali, the 6-liter does not go in regular cab or extended cab long bed trucks, and manual transmissions are not offered.

Walkaround

The front-end design of the 2008 GMC Sierra emphasizes the truck's wide stance. The GMC emblem is set amid dark horizontal bars in the middle of an upright and chrome-surrounded grille. The headlamps are a pair of stacked, jeweled lenses. The front bumper features round fog lamps and a wide air intake and wraps around the sides of the truck to the front lower edge of the front wheel wells. The Denali gets its own chromed grilles, both the upper section and the air vent below the front bumper, and the bumpers are painted to match. The hood has a pair of long, narrow V-shaped power bulges and leads back to a steeply raked windshield. The windshield is tilted back for improved aerodynamics and enhanced highway fuel economy. The side view features slightly bulging and elongated fender flares that sweep down behind the headlamps. The sides of the cargo bed are higher than on previous models, and the exterior of the tailgate is sculpted, enhancing the rear view of the truck. Stacked tail lamps are on either side of the tailgate. Two new reds are available on a truck that looks taller and stronger than its predecessor, yet also has improved aerodynamics. Engine choices include a V6, a 4.8-liter V8, four 5.3-liter V8s (iron and aluminum blocks, some E85 flex-fuel capable, all with Active Fuel Management that disables some cylinders for fuel economy), a 6-liter V8, all with four-speed automatic transmissions, and on the Denali only a 6.2-liter and six-speed auto. Except for Denali, EPA ratings run 13-15 city, 17-20 highway, and on E85 those numbers drop substantially. An optional cargo management system is available for the bed with side rails and various cargo-carrying and cargo-controlling boxes and dividers and tie-downs. The GMC Sierra and Chevy Silverado are built on the GMT900 platform that debuted in 2007 and shares many underpinnings with the Yukon SUV. The pickups get a unique rear suspension and frame section that is 245 percent stiffer. The Sierra and Silverado share mechanical components, with the exception of the unique features found on the Sierra Denali. Compared with the previous-generation, the current frame is 234 percent stiffer in torsional rigidity, 62 percent more resistant to bending and 136 percent stiffer laterally. This yields a smoother ride and better handling. It also allowed the engineers to reduce the gap between the truck bed and passenger compartment as well as the gaps between fenders and bumpers, all of which enhances aerodynamics and fuel efficiency. The front suspension uses a coil-over-shock setup and the rack-and-pinion steering gear is mounted to the engine cross member frame. The truck also has a new rear axle design with shocks absorbers mounted outboard and more upright for better dynamic control.

Interior Features

The GMC Sierra SLT boasts interior features popularized by the Yukon sport utility, providing a much more upscale environment for the driver and passengers. GMC hasn't forgotten about owners who use their trucks for work, however. So other Sierra models use a pure pickup interior with more function, like dual glove boxes, and less luxury. The "pure pickup," as it's called, has a unique dashboard that is more driver-oriented and has larger switchgear and door handles that are designed to be easily manipulated by those wearing work gloves. The pure pickup interior includes a 40/20/40 split front bench seat with the center section folding down to provide a large storage compartment and wide armrest. The SUV-style luxury-oriented interior puts audio and ventilation system controls more easily within reach of the front-seat passenger and has two front bucket seats with a fixed center console with assorted storage compartments. Either dashboard sports full analog instrumentation, and many have more info available through digital display. Operating controls are GM simple, especially on the pure pickup, while the top-line models central dash has many small white-on-black buttons that may require a short learning curve. Some drivers report peculiar ergonomic details as the steering wheel is slightly offset from the seat centerline. Rear seating is provided for three people in the extended and crew cab versions, with 34.3 inches of rear legroom in the extended cab and 38.7 in the crew cab, space is similar to Ford's F-150 and Nissan's Titan, and smaller than Dodge's Quad and Mega Cabs and Tundra's Double and CrewMax cabs. The crew cab rear seat is split 60/40 and can folded up individually for a flat load floor; this arrangement is optional on extended cabs. Access to the rear seating area of the extended cab is eased by rear-hinged doors that open to nearly flush with the bed sides. Sitting in the back seat of the extended cab is made more pleasant thanks to the fact that the windows in the rear access doors power fully down.