United Auto Workers members passed a four-year contract agreement with Chrysler LLC on Saturday despite significant dissent from some workers, the union said.

The union said 56 percent of production workers and 51 percent of skilled trades workers voted for the pact. The percentages voting in favor were much higher among clerical workers and engineers represented by the union.

The new contract covers about 45,000 active workers at Chrysler and more than 55,000 Chrysler retirees and 23,000 surviving spouses. It will expire on Sept. 14, 2011.

UAW and Chrysler bargainers reached the agreement Oct. 10 after a six-hour strike. The deal came the same day the union announced that General Motors Corp. workers had approved a similar contract.

Many workers opposed the agreement because it establishes lower wages for some noncore, non-assembly workers. The contract also doesn't make as many promises for future work at U.S. plants as the contract approved by the GM workers.

"Our members had to face some tough choices, and we had a solid, democratic debate about this contract," UAW President Ron Gettelfinger said in a statement. "Now we're going to come together as a union — and now it's on the company to move ahead, increase their market share and continue to build great cars and trucks here in the U.S."

Chrysler, which became a private company in August when it was bought by Cerberus Capital Management LLC, said the agreement will make the company more competitive.

"We are pleased that our UAW employees recognize that the new agreement meets the needs of the company and its employees by providing a framework to improve our long-term manufacturing competitiveness," Tom LaSorda, Chrysler's vice chairman and president, said in a statement.

The union now turns to Ford Motor Co., the last automaker to negotiate in this year's round of contract talks. Talks with Ford were expected to proceed throughout the weekend.

At the last plant to vote, in Belvidere, Ill., 55 percent of workers opposed the contract early Saturday, according to a person who was briefed on the vote. The person requested anonymity because the person wasn't authorized to speak on vote totals.

It would have taken an overwhelming turnout and "no" vote by Belvidere's 3,300 workers for the contract to fail, according to some of the people opposed to the agreement.

Belvidere assembly line worker Gwen Vanover said Friday she decided to vote "yes" because while she could survive a lengthy strike, she wasn't so sure about the company.

"I'm not happy with it. I don't think it's the best contract," said Vanover, 52, of Belvidere. "I don't even really mind being out of work if I thought we could get something better. But in order for something to be there for the next generation, it's better to lose the battle than to lose the war."

Industry analysts believe the contract will make the company more competitive with Japanese automakers. But many union members were concerned about the provision that would pay $14 an hour to about 11,000 workers considered non-core, while Chrysler assembly workers now make a starting wage of $28.75 per hour.

As recently as Tuesday the pact was losing after large locals in Kokomo, Ind., voted it down, but workers at four Michigan assembly and stamping plants in Sterling Heights and Warren had a strong turnout on Wednesday and voted largely in favor. The Sterling Heights and Warren votes pushed the favorable vote ahead.