SILAO, Mexico—Workers at two General Motors’ assembly plants here voted for a new independent union to represent them after ousting an old guard union last year, according to results announced Feb. 3.

The vote among the roughly 6,500 employees of the factories, which assemble transmissions and pickups, was a major test of whether a measure of freedom has come to Mexico, where pro-company unions held wages down for decades and drained manufacturing jobs from the U.S. When finally given the chance to vote by secret ballot on which union would represent them—something it took a U.S. labor complaint to achieve—the results from the voting Feb. 2-3 weren’t close.

The Independent Union of Auto Industry Workers, known by its initials in Spanish as Sinttia, won 76 percent of the roughly 5,500 votes cast. The old-guard Confederation of Mexican Workers, the CTM, which long dominated the plant, won less than 1,000 votes.

“I want all the workers to see it can be done, because this is the start of a new change in unionism,” the leader of the Sinttia independent union, Alejandra Morales Reynoso, said after the vote. “I think we are going to start showing all our colleagues that a real change can be achieved, not just here in Silao, but in the state, the country and in the whole world.”

In a statement, GM called it “an unprecedented exercise in democracy,” and said “General Motors will act in compliance with the law to work with the union representation elected by the workers.”

The United Auto Workers said in a statement it welcomed the results.

“The UAW congratulates the workers of GM Silao on forming a free, fair and independent SINTTIA union,” according to the statement. “We commend the Biden Administration and USTR (U.S. Trade Representative) for ensuring a fair election process and we look forward to a new era of free, fair, independent unions in Mexico.”

That was a reference to a U.S. government labor complaint filed last year under the U.S.-Mexico-Canada free trade pact. Under changes to Mexican labor law required under the USMCA, workers can now in theory vote out the old, pro-company union bosses. But in practice, the old union bosses resisted.