August 26, 2005
GM announces new six-speed automatic transmission co-developed with Ford
Milford, Michigan – General Motors’ new Hydra-Matic 6T70 six-speed automatic transmission, an advanced design with clutch-to-clutch shift operation for front- and all-wheel-drive vehicles, will debut in the all-new 2007 Saturn Aura midsize sedan.
Co-developed with Ford, the new six-speed joins two other six-speed transmissions already announced, as part of GM’s mission to produce three million six-speed automatics annually by 2010.
The 6T70’s operation allows for reduced complexity and compact packaging, while a wide, 6.04:1 overall ratio spread helps it deliver performance with fuel economy. The 6T70 can return up to eight per cent improved performance, with up to four per cent improved fuel economy, when compared with current front-wheel-drive, four-speed automatics.
Co-development of the transmission allowed it to reach production in less time, and enabled each company to reduce development costs by as much as fifty per cent. The companies will share a common design and many components, but Ford and GM each developed their own controls and calibrations to tailor the shift feel to fit their brand characteristics.
The transmission is rated for engines up to 315 horsepower and 280 lb-ft of torque. Shorter steps between gears enhance performance and feel, with less hunting on grades; the 6T70 also offers the capability of driver shift control. The engine is manufactured at GM’s Warren Transmission plant and will debut in summer 2006, when production begins on the 2007 Saturn Aura.