GM Canada president Kevin Williams has scheduled an appearance at the plant Friday morning when he is expected to announce new production.
Among the invited guests are federal Finance Minister Jim Flaherty and Brad Duguid, Ontario's minister of economic development and innovation.
GM has been tight-lipped on just what will be announced, including the size of its planned investment. However, speculation has centred on the new version of its popular Chevrolet Impala sedan.
"The media release General Motors put out doesn't specify the product, but my its my guess its the next generation Impala," said Chris Buckley, president of the Oshawa Local of the Canadian Auto Workers union.
Buckley said in an interview that all of the other products the union has bargained over the last several years have been announced and are in production.
"The only vehicle they have yet to announce was the next generation Impala so I'm going to assume tomorrow that they are, once and for all, going to make it official that our members in the Oshawa car assembly plant will producing the next generation impala."
GM's Oshawa operations have seen a number of positive changes over the last year or so, with new vehicle models and expanded production that has added two new shifts and 1,300 jobs.
In August, GM announced a $117-million investment to prepare the plant to build the new Cadillac XTS next year. The automaker said the that move would create or save 400 jobs on the flexible assembly line in Oshawa, site of the company's Canadian headquarters and main car-making operations.
However, union leaders have also been concerned by the company's decision to shift a percentage of the next generation Impala to an assembly plant in Michigan.
"The ratio has not been locked down yet, but we will share production with our counterparts in the United States," said Buckley, who noted the current versions is produced exclusively in Canada at the consolidated plant in Oshawa.
That plant, which currently employs some 2,400 CAW members, is scheduled to close in the first quarter of 2013. The new Impala would be produced at the flex plant, which currently makes the Chevy Camaro, Buick Regal and soon, the Cadillac XTS. About 2,000 CAW members currently work at the flex plant.
"So this is a good news story," Buckley said, "because it reconfirms the commitment on investment, reconfirms the products that we bargained — that we had recommitted during the auto crisis."
"But at the end of the day, we're still going to have a plant that's closing. So we are going to suffer job loss."
As a result, Buckley said the union will continue to press the federal and provincial governments help it convince General Motors to put additional products in Oshawa to keep the consolidated plant open.
"We have yet to be successful, but we are going to continue to try," he said.