General Motors said it would spend US$100m at two of its factories – $93m at the Romulus, Michigan propulsion plant and $7m at the Bedford, Indiana casting operations.

The Romulus investment will add machining capability while the Bedford investment will increase die casting capabilities. Both investments will support increased production of the 10-speed automatic transmissions used in the Chevrolet Silverado and GMC Sierra light-duty, full-size pickups. Work will begin immediately at both locations.

"Demand for our Chevrolet Silverado and GMC Sierra full-size pickups continues to be very strong and we are taking action to increase the availability of our trucks for our dealers and customers," said Phil Kienle, GM's VP of North America manufacturing and labour relations.

Romulus currently builds V6 engines and 10-speed transmissions used in a variety of vehicles. The plant originally opened in the 1970s as part of GM Detroit Diesel Allison Division making diesel engines and components. The plant began to produce engines in the 1980s, and through the years, has produced over 10.8m V8 engines and over 6.6m V6s.

Bedford Casting Operations is located in south central Indiana and is one of the world's leading aluminum die casting facilities making transmission casings, converter housings, heads, and small petrol engine blocks used in GM vehicles.