General Motors Corp. says it will make investments totaling $393 million in two Ohio parts operations.

The auto maker, which earlier this week said it would pour $63 million into a Saginaw, MI, casting plant, says it will sink $332 million into its Toledo, OH, transmission plant for production of a new front-drive 6-speed automatic. Another $61 million will be spent at its Defiance, OH, casting plant.

The Toledo facility investment will include renovation and new machinery, equipment and special tooling to support production of the new Hydra-Matic 6T40/45 transaxle.

In addition, GM says it will spend another $57 million for vendor tooling, containers and investments at other locations necessary to support the Toledo operations. Construction will begin in July, and production of the transmission will be launched in February 2010. The project will retain 600 hourly jobs at the plant, the auto maker says.

The Toledo investment comes on top of a $540 million outlay GM announced last year at the facility for production of a rear-drive 6-speed automatic.

In Defiance, GM will install precision sand-casting technology to produce aluminum engine blocks for its high-feature 3.6L V-6. The technology is the same as that going into the Saginaw plant, which also will supply castings for the 3.6L engine.

The Defiance investment will include refurbishment of a 120,000-sq.-ft. (11,148-sq.-m) portion of the plant, which will begin in June. Production is slated to start in December 2009, allowing 120 hourly jobs to be retained.