The majority of Ford's hourly workers have signed the grievance that protests Ford reinstating merit pay in 2010 just for salaried workers, the Detroit Free Press reported Tuesday.
The United Auto Workers contends their contract, which expires Sept. 14, mandates all Ford employees share in the sacrifices and rewards.
UAW and Ford are scheduled to begin contract talks in July.
"It's extremely important that the equity-of-sacrifice grievance be resolved before the contract expires," said Nick Kottalis, chairman of UAW Local 600 in Dearborn.
"And it must provide something for the membership of UAW Ford employees," Kottalis said.