DETROIT – The next two days will be critical in deciding the fate of a new four-year contract between Fiat Chrysler and the United Auto Workers.

In early voting, workers at several factories rejected the deal, but those at a pickup truck plant in Warren, Michigan, voted in favor.

UAW leaders are still hoping that the contract will pass at large factories in Belvidere, Illinois; Sterling Heights, Michigan; and Toledo, Ohio. Results should be tallied Wednesday or Thursday at the plants, which together employ more than 12,000 workers.

The UAW, which represents about 40,000 Fiat Chrysler workers, reached a tentative agreement with the company two weeks ago that includes pay raises, the potential for increased profit sharing and a $3,000 signing bonus. But the raises don’t bring an end to a two-tier wage structure that pays workers hired before 2007 more money. The contract also allows the company to shift some car production to low-wage Mexico, replacing it with new trucks and SUVs that carry higher price tags to cover higher U.S. wages.

If the deal is rejected, the union could go back to the bargaining table with Fiat Chrysler, also known as FCA US LLC, or it could shift bargaining to either Ford or General Motors. It could also go on strike. Workers at all three companies have stayed on the job under extensions of their old contract, which expired on Sept. 14. Usually the first deal reached serves as a basic template for the other two companies, although UAW President Dennis Williams made it clear he expects to get more from GM and Ford, which are more profitable than FCA.

On Tuesday afternoon, the union gave Ford notice that it intends to strike at an F-150 pickup truck plant in Claycomo, Missouri, near Kansas City starting this weekend. Union Vice President Jimmy Settles said in a notice to members that Ford isn’t bargaining in good faith over local contract issues that include staffing provisions, heat stress and skilled trade schedules.

The 120-hour notice expires at 12:48 p.m. Sunday at the sprawling 7,500-worker factory, which also makes the Transit commercial van.

Ford says it’s working to avoid a strike and it’s confident it can negotiate a fair and competitive deal with workers.

At Fiat Chrysler plants, voting is difficult to track because plant-level union officials usually release only percentages of votes for and against the contract.

At the company’s engine plant in Trenton, Michigan, south of Detroit, 80 percent of production workers voted against the deal last week.