Ford Motor Co.  said Monday it will invest $850 million in some of its Michigan operations, which should help create up to 1,200 jobs in the state by 2013.

The additional investment will be made between 2011 and 2013, with most of the money funneled into expanding production of Ford’s 6-speed transmissions at two plants in Livonia and Sterling Heights. Investments will also be made at the company’s axle plant, also in Sterling Heights, and the Dearborn Truck plant, which produces the F-150.

The automaker expects to create about 900 jobs hourly jobs and 300 salaried positions. The state’s unemployment stood at 13 percent in September, making it the second highest in the nation behind Nevada.

This investment is in addition to the $950 million the company previously said it would spend to change its Michigan Assembly Plant from producing large sport-utility vehicles to cars such as the Focus, which arrives in show rooms next year.