General Motors has invested $20 million two Michigan assembly plants to increase capacity to produce its 10-speed automatic transmission and crossovers such as the Chevrolet Traverse, the company has announced.

GM will invest $20 million in its Romulus propulsion plant, which now builts V-6 engines and 10-speed transmissions for several cars, trucks, and crossovers. Since 2009, GM has invested more than $880 million in the plant.

The Romulus plant opened in 1976 as part of GM's Detroit Diesel Allison Division to make diesel engines and components. It began producing engines in the 1980s, and has produced over 10.8 million V-8 engines and over 6.6 million V-6 engines.

GM will also invest $36 million in its Lansing Delta Township assembly plant that builds the Traverse and Buick Enclave three-row midsize SUVs. The Lansing Delta Township plant, which is GM's newest, opened in 2006. Since 2009, GM has invested more than $600 million in it.

At the moment, GM employs 51,000 workers in Michigan at 33 locations. GM spends more than $10 billion on more than 3,100 suppliers in the state each year.