U.A.W. Expands Strike to a Ram Plant in Michigan

In a major escalation of its six-week strike at the three large U.S. automakers, the United Automobile Workers union on Monday told 6,800 workers at a large Ram pickup truck plant in Michigan to walk off the job.

Union workers at the Sterling Heights plant, which is owned by Stellantis, the parent of Ram, Chrysler and Jeep, joined the strike on Monday morning. Shutting down production at the plant, the largest Stellantis factory in the United States, suggests there are still big gaps in contract negotiations between the automakers and the U.A.W., which is seeking raises of 40 percent over four years, better retirement benefits and other changes.

The union’s strategy in this strike is a departure from its past practice of striking all locations of one automaker before beginning negotiations with the next automaker. This time, the union started with a strike at one plant at each of the three carmakers — Ford Motor, General Motors and Stellantis — and has expanded them to other factories and warehouses to increase the pressure on companies that it said were not doing enough to improve their offers.

The new approach has kept the automakers off balance because they don’t know when or where the union will walk out next. It is also a way for the union to play the companies off one another. The union’s president, Shawn Fain, has offered side-by-side comparisons of the three companies’ offers on wages, retirement benefits and other negotiating terms in online videos.

On Friday, General Motors put forward a more lucrative contract proposal. By calling for the strike at the Sterling Heights plant, the U.A.W. is trying to pressure Stellantis into at least matching the terms that G.M. offered.

“Stellantis has the worst proposal on the table regarding wage progression, temporary worker pay and conversion to full-time, cost-of-living adjustments, and more,” the U.A.W. said in a statement on Monday.

In its offer, G.M. proposed raising workers’ wages by 23 percent over four years. That would lift the wage for all full-time workers from $32 an hour to more than $40, giving them a base pay of about $84,000 a year, not including overtime or profit-sharing bonuses.

The walkout at the Ram plant is the first escalation in the strike since the U.A.W. called 8,700 workers to leave their jobs at Ford’s largest plant, in Louisville, Ky., on Oct. 11. That plant produces the Super Duty version of the popular F-series pickup trucks and the Ford Expedition, a full-size sport utility vehicle.

In a statement, Stellantis said the company was “outraged” by the expansion of the strike, noting that it made a comprehensive new proposal to the union on Thursday morning and was waiting for a counterproposal from the U.A.W.

“Our very strong offer would address member demands and provide immediate financial gains for our employees,” the company said. “Instead, the U.A.W. has decided to cause further harm to the entire automotive industry as well as our local, state and national economies.”

U.A.W. members were already on strike at one other Stellantis plant, a factory in Toledo, Ohio, that makes the Jeep Wrangler and the Jeep Gladiator. The union has also struck 20 Stellantis spare-parts distribution warehouses around the country.

Ram is one of the most important of Stellantis’s many auto brands, because of the popularity and higher prices that pickup trucks command in the United States. The plant, about a 25-mile drive north of downtown Detroit, makes Ram 1500 pickup trucks, the brand’s top-selling vehicle. In the first six months of this year, Stellantis reported about $12 billion in profit, more than G.M. and Ford combined.

Wes Lutz, the owner of Extreme Dodge, a car dealership in Jackson, Mich., said he had been watching the inventory on his lot dry up over the past six weeks and had struggled to replace parts on his customers’ vehicles.

The Ram 1500 is the best-selling model at his dealership. Jeep models, some of which were targeted in the initial walkout, are also popular. Mr. Lutz said he was selling everything he had while getting a “slow drip” of new inventory.

“I think it’s getting to a crucial time now,” Mr. Lutz said. “Another month and the faucet is going to be completely turned off.”

Stellantis is a relatively new company, formed by the merger of Fiat Chrysler and Peugeot, the French automaker, in January 2021. The combined company is based in Amsterdam and has its U.S. headquarters in Auburn Hills, Mich., near Detroit.

Altogether, about 40,000 workers at Ford, G.M. and Stellantis are on strike across the country. In addition to the Stellantis locations, the union is on strike at Ford plants in Michigan, Kentucky and Chicago and two plants in Michigan and Missouri and 18 warehouses owned by G.M.

The three automakers combined employ about 150,000 U.A.W. members.

J. Edward Moreno contributed reporting.