Voting is scheduled to end Tuesday on a labor contract between Ford and the United Auto Workers union.
Two Chicago area factories have already overwhelmingly rejected the plan that would have created 1,100 new jobs at the plants and were told to prepare for a strike.
Chicago Mayor Rahm Emanuel maintains the contract is a good deal.
"I thought it was a good agreement for Ford. I thought it was a good idea for Ford workers, and I think it's a good agreement, in our particular case, for Chicago," said the mayor at a press conference on Friday. "Obviously, both Ford management and UAW leadership thought it was a good agreement, because that's why they agreed to it."
As of Sunday evening, 62 percent of UAW members nationwide had voted in favor of the contract, according to the UAW Ford Division's Facebook page. Thirty-eight percent had voted against the tentative deal.