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General Motors New Hydra-Matic RWD Six-Speed Automatic Transmission Family
ISSN: 0148-7191, e-ISSN: 2688-3627
Published April 03, 2006 by SAE International in United States
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The Hydra-Matic 6L80 is General Motors first model of a new, four-variant, rear wheel drive (RWD) six speed automatic transmission family. The four variants are the 6L45, 6L50, 6L80 and 6L90. The new, high performance 6L80 will debut in 2006 model year performance vehicles, including the Chevrolet Corvette C6 and new Cadillac STS-V and XLR-V. By 2007, GM expects to use the RWD six speed family in as many as 25 different car, truck and SUV models in RWD, 4WD and all-wheel drive configurations.
While the Hydra-Matic RWD six-speed family was designed with four variants, the built in modularity requires only two different basic diameters of parts and “flexing” on part width (length) depending on specific torque requirements. This built in modular design enables a tremendous amount of part sharing and part scaling. Modularity minimizes engineering resources, improves investment and piece cost, speed to market and allows for a wide bandwidth of vehicle and engine applications. The current bandwidth of applications ranges from 2.5 L to 6.6 L engines. The planned engine torque capacity for the family ranges from 258 lb.-ft. to 520 lb.-ft. (350 Nm to 705 Nm) with flexibility for future growth.
The RWD six speed family is expected to improve both fuel economy and acceleration performance. As an example, the 6L80 is expected to improve fuel economy by as much as four percent, while improving 0-60 mph times by as much as seven percent when compared to the current four speed automatic that it replaces. This was accomplished by a wider overall ratio spread of 6.04:1 compared to the typical 4.0:1 for conventional four-speeds.