UAW members began picketing at three plants operated by General Motors, Ford and Stellantis early on Friday after talks between the union and management failed to narrow differences on contract terms and pay.
The strike, involving some 12,700 workers at three assembly plants in Michigan, Missouri and Ohio, is expected to halt production of popular car models including the Ford Bronco, Jeep Wrangler and Chevrolet Colorado.
The UAW has demanded a 36 percent pay rise over four years and the elimination of a tiered salary scale that requires workers to put in eight years before being eligible for the same compensation as veteran employees.
The “Big Three” carmakers have offered a pay bump of 17.5-20 percent, without other benefits and the changes to the wage system demanded by the union.
UAW President Shawn Fain said the union would not call a broader general strike for now, but all options would be on the table if new contracts are not agreed.
“They could double our raises and not raise car prices and still make millions of dollars in profits,” Fain said. “We’re not the problem. Corporate greed is the problem.”
Ford said it had bargained in “good faith” to avoid the strike and would continue to work towards an agreement that “rewards our employees and protects Ford’s ability to invest in the future”.
GM and Stellantis did not release a statement ahead of the midnight deadline for the strike.
GM’s top manufacturing executive Gerald Johnson said earlier that the UAW’s proposal would cost $100bn and would be “absolutely impossible to absorb”.
A prolonged strike could pose a challenge to the re-election prospects of US President Joe Biden, who has claimed to be the most union-friendly president in American history.