Leading a complete redesign of its full-size pickup models, General Motors has introduced light-duty versions of the 2007 GMC Sierra and Chevrolet Silverado. The heavier 2500HD and 3500HD versions will follow within three months, according to GM president and CEO Rick Wagner.

With full-size pickups accounting for 30% of GM's unit sales, the replacement for the current GMT800 generation plays a major role in the company's long-term turnaround plans, Wagner said at a media event held at GM's Milford, MI, test facility.

The new light-duty GMT900 trucks feature higher payload and towing capacities, improved fuel economy from advanced engine technology, new safety systems, including curtain-side air bags, and more sheet metal differentiation between the GMC and Chevy versions. Both versions are offered with regular, extended and crew cabs with a choice of three bed lengths, five suspension packages, eight powertrain combinations and a variety of trim levels.

Engine offerings for the 2007 Silverado and Sierra light-duty range from a 4.3L V6 to a 6.2L V8, with most fleet users expected to opt for GM's 315-hp. 5.3L V8, according to Dr. Terry Woychowski, vehicle chief engineer for full-size trucks.

Variable valve timing and GM's Active Fuel Management (AFM) technology achieve a 7% improvement in fuel efficiency over previous versions of the engine, with similar numbers for the 6L 367-hp. V8, Woychowski told Fleet Owner. AFM shuts down four of the engine's eight cylinders when power demand is low and seamlessly activates all eight when necessary without any driver interaction.

The 5.3L has an EPA mileage rating of 16 mpg city and 22 mpg highway in 2WD drive models, and 16/21 in 4WD models.

The chassis has also been redesigned for the 2007 Sierra/Silverado, with greater torsional stiffness, wider front and rear tracks, coil-over-shock front suspension, a new rack-and-pinion steering system, and an Eaton automatic locking rear axle. GM's StabiliTrack electronic stability control has also been redesigned to improve rollover mitigation, according to the company, and will be standard on all 2007 crew cab models.

Payload capacity for the new light-duty GM pickups tops out at 2,160 lb., and towing capacity ranges from 1,564 to 10,500 lb.

Major cab changes include a rear access door for extended-cab models that opens 170 deg. and has fully retractable power windows. Tighter tolerances have also reduced gaps between body panels and improved overall aerodynamics, GM said.

Inside, the GMT900 has undergone a number of major changes that include more storage space and increased passenger room. The new light-duty models will be available at GMC and Chevrolet dealers in the fourth quarter, according to GM officials. The HD versions will be introduced in October, with availability early next year.
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