Members of the United Auto Workers went on strike at General Motors Co. plants nationwide at midnight Sunday night, sending 46,000 workers to picket lines in the union's first walkout since the automaker emerged from taxpayer-funded bankruptcy a decade ago.

The UAW on Sunday night said "dialogue is continuing" with the Detroit automaker, but a GM spokesman said talks were halted amid an increasingly acrimonious atmosphere and an unorthodox response by GM that breaks with decades of bargaining protocol. The UAW said a bargaining session is scheduled at 10 a.m. Monday.

More: Daniel Howes: Federal corruption probe, mistrust fuel UAW-GM strike

More: Strike will hurt rank-and-file workers before GM, experts say

As the clock struck just before midnight, workers streamed out of the GM Flint Assembly Plant and moved toward their vehicles on the lots. In single lines and orderly fashion, their shift done, they drove onto Van Slyke Road, just across from UAW Local 598's headquarters, to the sounds of car horns piercing the night.

Pickets had massed outside the plant and were chanting: "One union" and "Mighty, might union" as more and more workers joined the picket line as rain competed with the union shouts and honking horns.

Ray Atherton from Flushing stood across Van Slyke smiling, watching vehicles exit early Monday, saying it reminded him of the strike in 1998: “This is my third one,” said Atherton, a GM truck driver for 25 years. “In '98, we were out for 56 days. I hope it doesn’t go that long.”

About 100 others gathered Monday morning at the Detroit-Hamtramck plant, where UAW members, some representing workers from Detroit's Big 3, carried signs and sported red UAW shirts. What happens at GM, they said, sets the tone for the rest of them.

“UAW — we’re all a big family,” said Louie Pahl, president of Local 1700 at Fiat Chrysler’s Sterling Heights Assembly Plant. “It doesn’t matter if you’re Ford, GM or Chrysler, Aramark … anything that’s UAW, we’re all brothers and sisters. We’re all from the same family when it comes down to it.”

Temp worker Chrishonda Starks, 41, of Flint said she wanted to hear how GM's temporary employees would be addressed in a new contract. Like Atherton, she wants the two-tier wage scale abolished.

“It’s hard," she said. "I have to tell people ... who have served less time to hang in there and that it’ll be worth it when they receive a permanent position."

President Donald Trump earlier had weighed in: "Here we go again with General Motors and the United Auto Workers," he wrote on Twitter. "Get together and make a deal!"

In a surprisingly detailed response to Sunday's strike announcement and before the walkout, GM outlined its offer to the union that promises more than $7 billion in investments over the life of a new contract. It said it would create more than 5,400 jobs, boost base wages, pay lump-sum bonuses, improve benefits — and, The Detroit News has learned, rescue its Detroit-Hamtramck Assembly plant from closure and build a new battery plant near the idled Lordstown plant in Ohio.

“We presented a strong offer that improves wages, benefits and grows U.S. jobs in substantive ways and it is disappointing that the UAW leadership has chosen to strike at midnight tonight," the automaker said in a statement Sunday. "We have negotiated in good faith and with a sense of urgency. Our goal remains to build a strong future for our employees and our business.”

UAW Vice President Terry Dittes sent a letter to Scott Sandefur, vice president of Labor Relations at GM, on Sunday stating: "Over the last two months, we have met with GM representatives countless times in an effort to resolve many important issues raised by our members."

Dittes wrote that the union was disappointed that GM waited two hours before the contract expired on Saturday night to make what the union considered "its first serious offer." If the union received that offer earlier, he added, it may have been possible for the two to reach a tentative agreement and the strike may have been avoided.

Patty Thomas, 63, a GM worker at the Detroit-Hamtramck plant, wore a red UAW shirt and held her picket sign high early Monday outside. She said she wants GM to retool her plant, which is scheduled to end production in January. Proposed contract details floated earlier that GM may use the plant to build an electric vehicle there didn't excite her.

“They may give us that and then take away our wages, take away our health care,” Thomas said. "They give you one thing to get rid of another. I’d have to see the whole package.”

Specifically, GM said it offered investments in eight facilities in four states. It proposed introduction of an all-new electric truck, as well as opening the first union-represented battery cell manufacturing site in the U.S.

The electric truck would be built in GM's Detroit-Hamtramck Assembly plant, according to two sources familiar with the situation, effectively rescuing the plant from the "unallocated" list and securing its future. GM proposed building the battery plant in northeast Ohio's Mahoning Valley, cushioning the impact of the closure of the automaker's sprawling Lordstown complex and its impending sale to Lordstown Motors Corp.

GM also proposed additional new vehicle and propulsion programs; base wage or lump sum increases in all four years; improved profit-sharing formula; ratification bonuses of $8,000; and retention of health care benefits, with new coverage for autism therapy, chiropractic care and allergy testing.

It's not typical for automakers to release details of contracts, but Art Wheaton, an automotive industry specialist at Cornell University's Industrial and Labor Relations School, said GM likely decided to release the highlights "to sway public opinion." He called the UAW's decision to strike a "risky strategy ... because now you are going to have to be able to get people to go back in."

On Sunday, the Teamsters said 1,000 of its members would stand in solidarity with the UAW and not haul any GM product. Teamsters Spokesman Bret Caldwell said its members haul "a very large percentage" of GM product to dealers across the country.

The UAW-GM confrontation comes as the federal investigation into UAW corruption is reaching the highest levels of the union, including the indictment of Region 5 Director Vance Pearson that also implicates "UAW Official A" and "UAW Official B." Citing sources, The Detroit News identified UAW President Gary Jones as "Official A" and his predecessor, Dennis Williams, as "Official B" in a years-long scheme that federal investigators say misused union money.

The union and GM likely will struggle to reach an agreement as long as the “big cloud” of the federal investigation into UAW corruption hangs over the union, said Marick Masters, business professor and former director of labor studies at Wayne State University.

“I think it will be difficult for them to get an agreement they can sell to the membership,” he said. “They aren’t going to get an agreement with at least some concessions. Whatever tradeoffs they make the membership will view somewhat skeptically because of what hangs over their head.”

Before GM released details of its proposal, Dittes said the union is trying to secure fair wages, affordable health care, job security and a path for temporary workers to get permanent seniority.

"What we are asking of General Motors is simple and fair," said Dittes, director of the UAW GM Department. "We are standing up for fair wages, we are standing up for affordable quality health care, we are standing up for our share of the profits. We are standing up for job security for our members and their families."

Brian Cannon, 57, an operations technician, was heading home at 2:30 p.m. Sunday at the end of his shift at the GM Lansing Delta Assembly Plant. Told about elements of GM’s offer, such as the company’s promise to keep the Detroit-Hamtramck plan open and build a battery plant in Ohio, the 33-year GM veteran said there must be other things the union is bargaining for that are important for the future.

“It’s all about money, I guess," Cannon said. "That’s what I’m working for, money so I can take care of my family and such. But some things you got to stand for or you’ll fall for anything.”

In the bailout that rescued GM from an uncontrolled collapse into bankruptcy, the U.S. Treasury Department pumped $49.5 billion into the bailout of GM in 2008 and 2009 and lost about $11 billion of it on the sale of GM stock after the new GM emerged from bankruptcy.

The last time a national strike was called was in 2007 when the UAW struck GM. That strike lasted less than two days, idling 80 facilities and affecting 73,000 workers. In 1998, 9,200 workers walked off the job at two parts plants in Flint, shutting down production for 54 days.

"This is our last resort," Dittes said of the strike, adding that UAW members stood up and made "hard choices and sacrifices" to save the company following its 2009 bankruptcy. "It represents great sacrifice and great courage on the part of our members and all of us."

Prior to the news conference, UAW leaders from local units around the country met with Jones to hear details of GM's offer. The assembled leaders, numbering roughly 200, unanimously approved strike action.

Jones, the embattled president, did not attend the news conference. When asked the whereabouts of Jones, UAW spokesman Brian Rothenberg said: "I'm not his scheduler. Mr. Jones has a union to run. I don't see you asking GM where (CEO) Mary Barra is at every press conference."

Masters of Wayne State said "you would expect under normal circumstances that, unless someone were ill, they would be there today. That’s a conspicuous absence.”

Asked if Region 5's Pearson remained on the UAW's International Executive Board, Rothenberg said: "I am here to talk about our workers today. I am here to talk about the workers who are going on strike."

"This union exists to support our local unions," he said. "This strike is about our local union members and we will not be deviated ... because that is what's in their interest, that is they want and that is what we will do."

Dittes said in a statement Saturday night that while there had been "some progress in this set of negotiations" with GM, issues remained on health care benefits, wages, temporary employees, job security and profit-sharing.

In addition to the GM workers, 850 Aramark Corp. janitorial workers represented by the UAW at five GM facilities in Michigan and Ohio went on strike late Saturday. The union told GM workers early Sunday morning to cross the janitorial picket lines for their shifts.

Aramark workers do cleaning and other tasks at Flint Metal Center, Flint Engine Operations, Flint Assembly, Warren Tech Center and the metal center in Parma, Ohio. Flint Assembly builds the profit-rich Chevrolet Silverado and GMC Sierra heavy-duty trucks.

The UAW selected GM as the target company because of how profitable the automaker has been, experts have said, and because the automaker was moving to close four U.S. plants. GM generated $27.5 billion in profits over the past four years of the latest contract.

But the company announced in November that it needed to cut North American plant capacity. Four plants were "unallocated" of products, the first step towards closure. The plants include Warren Transmission, the Lordstown, Ohio, complex, Baltimore Operations in Maryland and Detroit-Hamtramck Assembly — which GM now proposes to save.

The union has said it will fight to get products reallocated to the affected plants. Wages are a top concern on both sides of the bargaining table: the union wants wage increases, and the automakers want to cut labor costs to align with what the foreign automakers spend in their U.S. plants.

Automakers — which want to cut costs to prepare for the costly investments they will have to make for Auto 2.0 and to deal with the impact from trade wars — are likely to push the profit-sharing model of paying workers more when they make more, but union workers want base wage increases in place no matter what.

UAW benefits are another sticking point. Benefits for UAW cost roughly 150% more than the U.S. average, according to the Center for Automotive Research.

“Bargaining isn’t getting what you want,” Wheaton said. “Bargaining is getting what both sides can live with. It’s a hard lesson for people to learn. If you make any promises and you can’t keep up with them, then it’s extremely tough to get it ratified.”

khall@detroitnews.com

Twitter: @bykaleahall

daniel.howes@detroitnews.com