General Motors will invest $170m to produce more efficient six-speed automatic transmissions, according to Reuters.

The company reportedly said the new transmissions produced at the Ypsilanti, Michigan, plant, which will debut in some 2007 Cadillac models, will offer better performance and improved fuel economy.

GM said it would invest $125m in the Ypsilanti transmission plant and another $45m in vendor tooling and other supporting facilities and equipment, the report said, adding that the additional investment will take the plant's production capacity to some 2,650 transmissions per day, up from 660 now.

According to Reuters, GM said by 2010 it expects to have as many of 10 variants of the new six-speed automatic transmissions in its cars and sport utility vehicles, with production of up to 3m of the units annually.

Reuters noted that GM's Ypsilanti transmission plant employs about 3,600 hourly and salaried workers. The plant began as a production hub for US warplanes during World War Two.