The Hydra-Matic 6T40 and similar 6T30, 6T45, and 6T50 are transversely-mounted six speed automatic transmissions produced by General Motors.
The 6T40, referred to in GM inner circles as the GF6, made its debut in the 2008 Chevrolet Malibu, available with the 2.4 L LE5 Ecotec engine making 164 horsepower (122 kW), and has since also been made available on the Chevrolet Cruze, Daewoo Tosca and Buick LaCrosse.
It features clutch-to-clutch shifting, eliminating the bands used on older transmission designs.
The 6T45 differs from the 6T40 in its use of heavier-duty components, allowing it to handle engines with greater torque.
The facility is currently capable of producing up to 300,000 Hydra-Matic six-speed automatic transmissions annually.