Jackson, Mich. (WKHM, Marc W. Daly) — Around 525 United Auto Workers members at Eaton Aerospace in Jackson walked off the job Monday morning, starting a strike over an expired union contract. About 100 workers, holding “UAW on Strike” signs, were seen picketing along S. East Avenue and E. Michigan Avenue just before noon. UAW leaders say more workers were expected to join.

The contract, which expired in July, has been a point of contention, with disputes over pensions and wage increases leading up to the strike. The union rejected Eaton’s last contract offer, and after the company turned down the union’s counterproposal on Monday, the walkout began. Workers plan to picket around the clock.

Eaton Aerospace has not yet commented.