DETROIT — General Motors on Monday said it plans to invest $71 million at two Ohio plants to enhance transmission production and prepare a casting facility for future components work.

GM will invest $39 million at its Toledo transmission plant to upgrade production of the eight-speed rear-wheel-drive transmission and $32 million at its Defiance casting plant. The investments will retain 240 manufacturing jobs.

The announcement builds on a $700 million investment announced last year at the Toledo plant, the Parma Metal Center and the DMAX plant that created about 450 jobs.

“Through these investments, GM continues to strengthen its significant manufacturing presence in Ohio,” Phil Kienle, vice president of North American manufacturing and labor relations, said in the statement. “Our Toledo and Defiance teams continue to focus on building world-class products for our customers and these actions are an investment in their futures.”

Toledo Transmission employs about 1,700 workers to build six-, eight- and 10-speed rear-wheel-drive transmissions and nine-speed front-wheel-drive transmissions used in a variety of vehicles across GM’s brands.

Defiance Casting Operations employs about 580 workers who manufacture cylinder block and cylinder head castings for inline-four, V-6 and V-8 engines.

GM said it has invested more than $3.3 billion in Ohio since 2009. The automaker also formed a $2.3 billion joint venture with LG Chem to build proprietary Ultium batteries in Lordstown that will create more than 1,000 jobs.

GM is required to repay $28 million in state tax incentives for closing its Lordstown assembly plant in 2019, the state and automaker also said Monday. GM sold the Lordstown plant to electric truck maker Lordstown Motors Corp. in November. GM must invest $12 million in the Mahoning Valley by the end of 2022, under an agreement with the Ohio Tax Credit Authority.

Reuters contributed to this report.