Tech Briefs
GM's new direct-injection diesel engine

The all-new 90° V8 Duramax Diesel 6600 for the 2001 Chevy Silverado and GMC Sierra.

The 2001 Chevy Silverado and GMC Sierra heavy-duty, full-size pickup trucks will go into production next fall with a new optional Duramax Diesel 6600 V8 engine and a new 5-speed automatic transmission designed specifically to handle all of the power and torque the new engine can deliver.

The growth in the pickup truck market over the past decade has increased rapidly, with a large portion of that market having heavy-duty hauling and towing needs. This is especially true for trucks equipped with diesel engines.

"Ten years ago, the industry sold fewer than 10,000 diesel pickups a year in the United States," said Gary White, Vehicle Line Executive, Full-Size Trucks, GM Truck Group. "Today, customer requirements for more power and torque, coupled with a need for more efficiency and durability, have raised demand far beyond that. GM President Rick Wagoner recently described the full-size truck platform as 'the economic engine that drives General Motors.' We think we'll see industry sales of more than 250,000 diesel pickups a year in the very near future."

The Duramax Diesel 6600 is an all-new, 90° V8 with Bosch common-rail direct-injection and an overhead valve (OHV), four-valves-per-cylinder design. It replaces GM's current 6.5-L turbo diesel and will provide Silverado/Sierra 2500/3500 customers with what GM says will be best-in-class power, performance, fuel efficiency, reliability, and durability. GM also says that it will provide best-in-class NVH characteristics, virtually eliminating the noise, shake, and roughness often associated with diesel powerplants. What GM will not reveal is the actual Duramax 6600 power or torque ratings, at least until shortly before production begins next fall. The new engine will meet Federal and California emissions requirements, allowing it to be sold in all 50 states.

The Duramax Diesel 6600 is the second in a growing family of GM-branded Duramax engines. The first was the Duramax Diesel 7800 introduced by GM for use in its 2000 model year medium-duty series trucks. The Duramax engine family is the result of a joint venture between GM and Isuzu Motors, DMAX Ltd. GM's relationship with Isuzu began in 1971 and was strengthened in 1997 when GM announced that Isuzu would develop diesel engines for GM. The Duramax Diesel family is domestically sourced, and will be produced in a brand-new DMAX, Ltd. facility in Moraine, OH.

Most of the diesel engines installed in light-duty trucks, have to be restricted in terms of output because the automatic transmissions cannot handle the increasesd power and torque. That is not the case with the Duramax Diesel 6600, which is mated to a new 5-speed Allison Transmission 1000 Series automatic transmission.

The 1000 Series is a fully automatic, electronic 5-speed with overdrive and a park pawl, and it offers planetary helical gearing similar to that now used in Allison Transmission's popular World Transmission. It will be produced in Allison Transmission's Indianapolis, IN, manufacturing facility, which has recently been updated and expanded as the result of a $275-million investment by GM. The 1000 Series is for general use in trucks of up to 9000-kg (19,850-lb) gross vehicle weight and 11,800 kg (26,000-lb) gross combination weight. It features 5 speeds forward (with 5th gear as overdrive), a torque converter with lockup clutch and integral spring damper, and fully electronic controls.