DETROIT (AP) — The United Auto Workers union says it has filed unfair labor practice complaints against Stellantis and General Motors for failing to make counteroffers to the union’s economic demands.

Ford was the only company of the Detroit Three to make a counteroffer, but it rejected most of the union’s proposals, President Shawn Fain told workers Thursday in a Facebook Live meeting.

Contracts between 146,000 auto workers and the Detroit companies expire at 11:59 p.m. Sept. 14, and Fain is once again threatening to strike.

He told members that the companies have been warned not to wait until the last minute to get serious about bargaining.

“The Big Three are either not listening or they are not taking us seriously,” Fain said, calling the refusal to respond “insulting and counterproductive,” and also illegal. He said the union filed the complaints with the National Labor Relations Board on Thursday.

Messages were left Thursday evening seeking comment from the companies.

The automakers have said they’re facing an uncertain transition from gas-powered vehicles to those that run on batteries. They’re also reluctant to take on labor costs that grow even farther beyond those at Tesla and foreign automakers with U.S. factories.

Fain, who won the UAW’s presidency this spring in its first direct election of officers by members, has set expectations high, telling workers that they can make significant gains if they’re willing to walk picket lines.

But even he has described union demands as audacious. Union members are seeking 46% pay raises over four years, restoration of traditional defined-benefit pensions for new hires, an end to tiers of wages, pension increases for retirees, and a 32-hour work week for 40 hours of pay.

Top-scale assembly plant workers now make $32 per hour, but the union’s proposal would raise that to $47.

Ford offered a 9% general wage increase over the life of the four-year contract, with lump sum payments instead of the union’s proposed cost-of-living adjustments, Fain said. The company also rejected demands to end tiers of wages, instead proposing that it take six years for new hires to reach the top of the pay scale rather than the current eight, he said.

Ford also turned down union demands to increase pension payments to retirees and for companies to pay workers if their plants are closed, Fain said. And it still plans to move battery work to what Fain called low-paying jobs outside of Ford at joint venture battery plants.

“Our union isn’t going to stand by while they replace oil barons with battery barons,” Fain said.