General Motors will make a $245 million investment in its powertrain plant in St. Catharines, Ont., a project expected to secure as many as 400 jobs.

The plant will be expanded to produce fuel-efficient, six-speed transmissions starting in early 2012, GM said.

This is the second piece of good news for the St. Catharines site in the last few months. In April, GM said the plant would receive a$235 million investment tied to V-8 engine production, starting in 2013. Combined, the projects will secure about 800 jobs at the plant.

Wayne Gates, president of Local 199, Canadian Auto Workers, said the investments brighten the long-term outlook for employees at the plant.

A year ago, GM needed financial support from the federal governments of the United States and Canada in order to survive.

“I think everybody was worried for their jobs,” Gates said.

But Gates said the new projects will probably have a life span of 15 to 20 years, and with many workers at the plant having 25 or more years’ experience, the new projects will help them reach retirement. He hopes that within a few years, GM will hire younger workers, as well.

The latest investment for St. Catharines was first talked about in September 2008 but was not confirmed as a project until Tuesday. GM said the project was moved ahead by four months to meet strong customer demand for its vehicles.

The back-to-back announcements for St. Catharines echo what has happened at GM’s Town of Tonawanda engine plant. The River Road site was chosen this year for a $425 million investment tied to a next-generation, four-cylinder Ecotec engine and a $400 million investment related to a “Generation V” V-8 engine.

Gates said the investments on both sides of the border also benefit small businesses around the plants, providing assurance of GM’s commitment to those locations for a number of years.