New York(CNN Business) The long General Motors strike is finally over, as members of the United Auto Workers union voted in favor of a four-year labor deal to end the walkout.

The rank-and-file members voted 57% in favor of the deal, according to the union. The labor contract was reached between union and company negotiators on Oct. 16, but strikers remained on the picket lines until it was ratified.

GM plants will resume work as soon as possible, with some workers returning over the weekend and others on Monday, according to two company sources familiar with plans.

The strike by nearly 50,000 hourly GM workers started Sept. 16, nearly six weeks ago. It is the largest against a US business since the last GM strike 12 years ago. But that strike was over in less than three days. This strike is the longest auto industry work stoppage in more than 20 years, and the longest nationwide auto strike in 50 years. GM has lost about $1.75 billion due to the walkout, according to an estimate from Anderson Economic Group, a Michigan research firm.

The deal was reached between union and company negotiators more than a week ago, although members stayed on the picket line until the ratification process could be completed.

Strikers have received strike benefits of only $275 a week. That's far below the more than $30 an hour that veteran UAW members make.

The new contract will pay the hourly workers an $11,000 signing bonus, which should help them recoup much of their lost wages, although GM was offering a signing bonus even before the strike started.

Under the deal, wages for most veteran workers will rise by 6% during the four-year life of the contract to $32.32 an hour. The union also won a way for many temporary workers to be hired as permanent employees as well as a quicker end to the two-tier wage system instituted after the 2009 bankruptcy than was in the previous contract language. The union also got the company to drop its demand that workers pay a larger percentage of their own health care costs.

Terry Dittes, the union's chief negotiator, said that the strikers' "sacrifice and courageous stand addressed the two-tier wages structure and permanent temporary worker classification that has plagued working class Americans."

GM also praised the deal and the workers.

"We delivered a contract that recognizes our employees for the important contributions they make to the overall success of the company, with a strong wage and benefit package and additional investment and job growth in our US operations," said a statement from GM CEO Mary Barra.

But the union failed in its efforts to save three plants -- an assembly line in Lordstown, Ohio, and transmission plants in Warren, Michigan, and Baltimore, where GM halted operations earlier this year. The union wanted GM to shift some of its production from Mexico, where the company built more than 800,000 cars and trucks last year, back to US plants, but GM refused.

While most of the autoworkers at those three plants have found jobs at other GM factories, many had to relocate to take those jobs. Anger among both union leadership and rank-and-file about those plant closings raised doubts about whether this labor deal would pass. But after nearly six weeks on the picket lines, workers were apparently willing to accept the closings for a chance to get back to work.

The union announced it will now focus on reaching a new labor deal for workers at Ford. The union had put negotiations with Ford (F) and Fiat Chrysler (FCAU) on a back-burner while it sought the deal with GM (GM).