DETROIT – General Motors introduces a number of significant enhancements to its medium-duty model lineup for the 2007- and 2008-model years. These include an all-new Chevrolet and GMC W-Series, as well as revised diesel engines and exhaust systems to ensure that GM medium-duty trucks meet new, more stringent federal and state of California diesel emissions standards. The Chevrolet and GMC W-Series is all new for 2008, with a larger and more spacious cab that provides more side-to-side and front-to-back room on both standard and Crew Cab models. The all-new W-Series also features a new, more modern dashboard with easy-to-see gauges and warning lamps. The front of the cab features a removable panel for easy access to the wiper motor and linkage, electrical cab connections, and air-intake filters. Storage areas include in the seat backs, dashboard, glove box, overhead storage shelves, and rear storage organizer. Additional safety items found on the 2008 Chevrolet and GMC W-Series include a new seatbelt design; low-cut side windows; larger, 17-inch x 8-inch side mirrors with integrated convex sections; and available heated mirrors. W5500 and W5500 HD LWB models are powered exclusively by the overhead cam 5.2L 4HK1-TC turbocharged, intercooled, diesel engine. It delivers 205 horsepower and 441 lb.-ft. of torque and is mated to a new Aisin A465 heavy-duty six-speed automatic with double overdrive. Chevrolet and GMC offer the 2008 W-Series Onyx Edition, a fully loaded truck with a host of special features, including an air deflector; stainless steel wheel simulators; air conditioning; AM-FM CD player radio; and all-black exterior Onyx paint with silver highlights. The Chevrolet and GMC Onyx Edition are based on a 14,500-GVWR, 132-inch wheelbase, 14-ft. body W4500 model, and are powered by the 5.2L 4HK1-TC turbocharged, intercooled, diesel engine. Another addition to the Chevrolet and GMC W-Series lineup is the W3500 Gas Crew Cab. It combines the added interior room of a Crew Cab with the power and convenience of a gasoline engine. The W3500 Gas Crew Cab will be available later in the model year and will be powered by the 325-horsepower Vortec 6.0L V-8 engine mated to the Hydra-Matic 4L80 four-speed automatic with lockup torque converter and overdrive.