NEW STANTON, Pa. (AP) _ The last Volkswagen made in America rolls off the assembly line Thursday, when the West German automaker closes its only U.S. assembly plant in an area already hit hard by declining manufacturing.

''Ninety-nine percent of the workers here had their heart in this place, their heart and their soul,'' said Robert Resides, 47, of Derry. ''Everybody has in their mind: Why? What did we do wrong?''

Resides began working at the plant when it opened 10 years ago amid rolling dairy farmland about 35 miles southeast of Pittsburgh, bringing the promise of prosperity and lifetime employment.

Volkswagen says the workers did nothing wrong. The company cited slumping sales and increased competition when it announced Nov. 20 that it would close its Westmoreland County plant, dismissing 2,500 blue- and white-collar workers and ending its U.S. manufacturing venture.

Many workers blame trade policies, not Volkswagen, for the shutdown.

''This area was once the industrial base of the country,'' said Ronald Dinsmore, 45, of Jeannette, who also worked at the plant for 10 years. ''Now the steel mills are gone. The rubber companies are gone. The glass factories are gone.''

''We're getting beat by foreign competition,'' he said.

Layoffs began in March, when production of the Jetta model ended. The last Golf model rolls off the 1.5-mile-long assembly line Thursday, the last day of work for all but 700 to 800 employees who will remain to help mothball the plant, said VW spokesman Chet Bahn. By mid-September, about 150 employees will be left, Bahn said.

The Volkswagen still will be sold in the United States. Jetta models will be imported from West Germany and Golf models from Mexico, Bahn said.

Gov. Robert Casey has said finding a new occupant for the sprawling, modern plant is a top priority, but Dinsmore, shop chairman of United Auto Workers union Local 2055, said that doesn't ease concern about finding jobs now.

The average VW worker earned $14 to $16 per hour, a wage that is hard to match in the area, said Judy Wilson, supervisor of a jobs center in the plant.

''What I've seen so far is you have to relocate to get a high-paying job,'' Walter Smith, 40, of Trafford said. ''I'd like to stay in the area. My house is all paid for.''

Smith, an electrician, said he applied for benefits provided by the Trade Adjustment Assistance program that would enable him to attend a community college to learn new electronics skills. The program helps workers who lose their jobs because of foreign competition.

Many laid-off workers fear finding good work may mean leaving the area where they grew up and hoped to spend their lives.

''I don't know whether to move,'' said Edward Prevenslik, 46, of Ruffsdale. ''My biggest concern now is with my daughter and interfering with her in school.''

Prevenslik, a maintenance man at the plant for 10 years, has handed out resumes and studied want ads for about three months. He's concerned about making ends meet.

''In the fall, when my kids start back at school, it's going to be a little close,'' he said. ''My girl, clothes for her. ...''

Resides found work in early July, three months after he was laid off. His new job, as a truck driver, ends in October and requires some time spent on the road away from his family, but he's still grateful for temporary work.

''There are a lot of $3.50 an hour jobs that a person can grab onto, but it's not a liveable wage for anybody with a family,'' he said.

Jack Wilson of Mount Pleasant, a welder at the plant, said his age is a handicap.

''I'm 52 years old now and there's nobody who's going to hire me without knowing me,'' he said. ''Now when you get a job, everything's part time. If you have a family, you have to have benefits.''

Volkswagen is the largest employer in Westmoreland County, where the unemployment rate in May was 6.2 percent, compared to 5.6 percent for the nation.

The laid-off workers live in at least three counties near the plant so the shutdown probably will not dramatically change the unemployment rate in Westmoreland County, said Mike Acquaviva, spokesman for the state Department of Labor and Industry.

But the shutdown is already pinching the local economy.

''There's been a drop off in business, but I think we'll see more effect in the next six months,'' said Larry Holliday, manager of the 70-year-old Sam Levin furniture store in nearby Mount Pleasant. ''A lot of our customers are VW employees.''

Chrysler Corp. built the blue-and-silver plant beginning in 1968, but abandoned the project in a business slump in 1970.

Volkswagen, trying to capitalize on a market once dominated by its beetle, began looking for a U.S. assembly site and was lured to southwestern Pennsylvania by former Gov. Milton Shapp. The state spent more than $70 million to land the plant.

The first VW Rabbit rolled off the assembly line in April 1978, but plans to make 500,000 cars a year materialized in the increasingly competitive small car market.