Though once derided by GM insiders as a public relations ploy, hybrids are now en vogue as the automaker began series volume production of its 2-mode hybrid transmission at its Baltimore, MD, Powertrain plant in October. Marking the end of a $118 million investment at the facility, the 2-Mode transmission will be available on the ’08 Chevrolet Tahoe and GMC Yukon full-size SUVs in early 2008. GM claims the 2-mode hybrid system will help a 2WD Tahoe achieve 21 mpg in the city, a 50% improvement over a non-hybrid version powered by the same 5.3L V8. “That’s the same city fuel economy as a [’08 2.4L] Toyota Camry,” says John Buttermore, vice president of global manufacturing at GM Powertrain.
Initial plans call for Baltimore to produce 10,000 copies of the 2-Mode in its initial year of production, with plans to scale up output to as many as 40,000-units. The automaker is running the 2-Mode line at Baltimore on a single shift with a final assembly cycle time of 5.98-minutes, compared to 98-seconds for an Allison A1000 Series transmission, which is built in the same plant and used in GM’s heavy-duty pickups.
Baltimore workers fabricate the 2-Mode transmission’s gears, valve bodies, main housing and input housing on-site, while the rest is farmed out to suppliers. To accommodate 2-Mode production, the automaker added a cell at every station on the fabrication line and all were reprogrammed to accommodate assembly of either hybrid or non-hybrid part builds. A separate final assembly area also was added specifically for the 2-Mode. GM will add the 2-Mode to the Cadillac Escalade, as well as its full-size Chevrolet Silverado and GMC Sierra pickups, later in 2008. A transverse-mounted 2-Mode transmission, to accommodate front-wheel-drive applications, will be built at GM’s Ramos Arizpe, Mexico, plant in 2009.—KMK