General Motors Corp.'s Allen County plant was hardest hit when the company on Thursday announced summer shutdowns at its North American assembly plants.

The 2,600 workers at the plant will be idled for 11 weeks starting May 4.

GM has 1,300 employees at its Defiance, Ohio, foundry, which could be down for up to two months.

The summer layoffs are intended to reduce inventory at a time when car and truck sales are weak and GM is in tough talks with the creditors of parts supplier Delphi, on which GM says it depends.

The shutdowns include the usual two-week layoff when GM switches to a new model year. And in Defiance, it includes a weeklong shutdown already planned to start Monday.

Across North America, shutdowns will range from one week at the Bowling Green, Ky., plant, which makes Saturn Auroras and Chevrolet Malibus, to 11 at the Allen County plant that makes GMC Sierra and Chevrolet Silverado pickup trucks.

In a conference call, GM North America President Troy Clarke said the longest shutdowns will be at plants making products with the biggest inventories.

"We began the year with large inventories of trucks," he said.

That's partly due to the downturn in home construction. Builders typically buy pickup trucks, but they aren't now because they're strapped for cash, Clarke said.

GM also makes Silverados and Sierras at two Michigan assembly plants. The Pontiac plant will shut down for six weeks and the Flint plant for eight.

Asked why Fort Wayne will be closed longer, Clarke said GM makes different kinds of Sierras and Silverados at each plant.

"It's very specific to each plant and each model the plant makes," Clarke said. "The Fort Wayne plant, I think, is the only plant of the three that makes a standard-cab pickup truck, and that turns out to be one of our higher-inventory units right now."

The Defiance foundry makes engine blocks and transmission parts for various GM vehicles. Because it serves many assembly plants with different schedules, it's harder to say how long it will be idled.

"I'd say we're going to have six to eight weeks of down time at Defiance," GM spokeswoman Lynda Messina said. "As far as powertrain and stamping facilities go, we need a little bit of time to finalize our schedules."

Dennis Dugan, 55, works at the Allen County plant. Employees attended a meeting Thursday to learn of the shutdown.

"It doesn't surprise me," he said. "It's typical GM. They keep you hanging and keep you hanging without telling you anything, and then this."

Under the contract between GM and the United Auto Workers, GM will supplement the unemployment benefits hourly workers collect. They'll get roughly 70 percent of their take-home pay.

The Allen County plant also was idled for two weeks in March.

But other questions loom as GM works against a June 1 deadline to show the federal government that it can be profitable. The company says it will close plants and slash its workforce in exchange for billions of dollars in federal loans it says it needs to stay afloat. The company has yet to specify many of the cuts.

"There's a lot of questions, but not many answers anybody wants to give," Dugan said.

Dwight Chatham has been getting many of those questions. He's president of UAW Local 211, which represents workers at the Defiance foundry.

Chatham said workers are worried not just about the future of the foundry, but also of GM and the UAW.

"Everybody thinks I've got answers," Chatham said. "I say I get my information from the Internet and the newspaper like everybody else."

Pain from the shutdown will spread beyond GM.

"It's going to be terrible for the community and the vendors that supply GM," said Orval Plumlee, president of UAW Local 2209, which represents workers at the Allen County plant.

During the shutdown, GM won't be buying parts from a troubled industry that employs more than 66,000 in Indiana and more than 80,000 in Ohio, according to the Original Equipment Suppliers Association, an industry group.

In a statement Thursday, U.S. Rep. Mark Souder, R-3rd, said it was bad enough that thousands of area GM employees will lose 30 percent of their income during the shutdown. It will be even worse for the parts industry, which has shed thousands of jobs since the recession started in December 2007.

"I am even more concerned that a summer without orders for GM parts suppliers will result in more company closures, putting tremendous pressure on families who could lose even more than 30 percent of their income," Souder said. "Some smaller companies may not recover."

mschladen@jg.net