General Motors enters 2019 as the top carmaker in Mexico.

The distinction comes as GM plans to shutter four U.S. manufacturing facilities this year, putting thousands of jobs at risk and drawing political and labor criticism of its decision to produce so many vehicles in Mexico, particularly the new Chevrolet Blazer SUV.

GM's rise in Mexico is largely because of Nissan scaling back its sedan production there, slipping from the top position. GM, on the other hand, has been retooling its San Luis Potosi plant and Ramos Arizpe facility in recent years to shift to SUV and pickup production.

GM said its boost in production is to meet the strong demand for SUV and pickups, as sedans have fallen out of buyers' favor.

“Production levels in all markets fluctuate with customer demand. For example, the continued growth in crossovers, pickups and SUVs is driving increases in production and employment at GM plants in Flint; Arlington, Texas; and Spring Hill, Tennessee," GM spokesman Pat Morrissey said in an email.

In Mexico, GM and Nissan have been the top two automakers for decades and have "alternated positions depending on what has happened in their production levels," said Stephanie Brinley, principal analyst at IHS Markit.

While there has been a shift in some of GM's production plans, said Brinley, "This is more on Nissan pulling back production."

Cheap labor

Still, GM's rise in stature south of the border hits U.S. hourly workers in the gut, especially after GM announced in November it will close three assembly plants by the end of 2019, including Detroit-Hamtramck, Lordstown in Ohio and Oshawa in Ontario.

More:General Motors to close Detroit, Ohio, Canada plants

More:GM decision to close Detroit-Hamtramck met with shock, anger

Over the last few years, GM has created or shifted production to Mexico, including the Chevrolet Equinox and GMC Terrain SUVs and Chevrolet Silverado pickups, said UAW President Gary Jones.

"It is time for Americans to stand up for what we know is right for America. We must build where we sell," Jones told members last month. "It is time to say, ‘No,’ to corporate greed and ‘No,’ to exploiting cheap labor in a downward spiral for wages here and abroad."

In 2016, GM paid hourly workers in its Mexico plants about $1.90 an hour, according to a white paper by Alex Covarrubias, a professor at the University of Sonora in Northern Mexico. The current UAW contract pays GM hourly workers a start rate of $17 an hour and increases to about $28 an hour over an eight-year period, said a UAW spokesman.

Closing Detroit-Hamtramck, Lordstown, Oshawa and two transmission plants puts more than 6,200 jobs at stake. GM also plans to cut close to 8,000 salaried jobs this month. GM said it would save $6 billion by the end of 2020 with these moves.

More:Why these 4 GM plants should be worried about closure risk

Take on Mexico

All three plants are prepared to fight for new products to build, and see their main rival as Mexico. Last month, Canadian union leaders ran four full-page ads in the Free Press and The Detroit News and met with GM's senior executives to pressure the automaker to replace the Chevrolet Impala and Cadillac XTS sedans and the 2018 Chevrolet Silverado and GMC pickups presently built in Oshawa.

U.S. production of the Impala ends in March and Canadian production in the fourth quarter of 2019. Reports say the XTS ends production in late 2019. The redesigned 2019 Silverado and Sierra pickups are now built at GM's Fort Wayne Plant in Indiana. The heavy-duty versions of those pickups are built in GM Silao plant in Mexico.

Canada's union, Unifor, made concessions to help GM during its bankruptcy 10 years ago, said Jerry Dias, Unifor president. If GM shutters the plant, Dias warned that Canadians will stop buying GM cars. “They are naïve to believe that Canadians won’t betray them for their blatant disloyalty," said Dias. "When they needed us, we were there. Mexico never gave them a dime.”

More:Canadian union slams GM in ads over Oshawa plant closing

More:Canadian union vows to elevate the fight to save GM plant

Things could change

Brinley said just as GM is now in the top spot in Mexico, it could change back.

For example, in 2010, GM built about 559,000 vehicles in Mexico and Nissan made 506,000. But a year later, Nissan increased its production to 607,000 vehicles compared with GM's 543,000, said Brinley.

Brinley said GM had built 801,163 vehicles through November, at its three Mexico assembly plants. That's up by 67,000 compared with the same period in 2017.

Nissan built 717,108 vehicles at its four Mexican factories during that time, she said, down by nearly 71,000 from a year earlier.

At its San Luis Potosi plant, GM manufactures the Chevrolet Trax and GMC Terrain compact SUVs. It ended production of the Chevrolet Aveo compact car in 2017.

GM has said it will build the new Blazer at its plant in Ramos Arizpe. GM said at the time that decision was made, no U.S. plants had available production to build the Blazer. Ramos built the Chevrolet Sonic until 2017 and the Chevrolet Cruze compact. The Cruze is also built at Lordstown, but will be discontinued this year.

GM builds pickups in three plants: Flint, Fort Wayne and Silao, Mexico. GM has built pickups at Silao since the plant opened in 1995, it said.

Ready to build

GM has not added plant capacity in Mexico for 10 years, said a GM spokesman. He said GM is adding 1,000 jobs at its plant in Flint to prepare for the launch of the Silverado and Sierra Heavy Duty trucks this year.

“Our Silao complex is already producing the new generation of large pickups, while at Ramos Arizpe we will produce the new Blazer SUV,” said Ernesto Hernández, president and CEO of General Motors México, according to GM Authority and Automotive News Mexico. “We will continue with our projects and we are very happy to be able to maintain our manufacturing footprint in the country,” he added.

GM's production boost makes it the largest exporter of cars in Mexico, too. Through November, it exported 693,782 vehicles, said Brinley, mostly to the United States and Canada.

Through November, GM's exports from Mexico are up 15 percent, exports to the U.S. are up 10 percent, but GM's exports from Mexico to countries other than the U.S. or Canada rose 40 percent compared with the same period in 2017, said Kristin Dziczek, vice president of Industry, Labor & Economics at the Center for Automotive Research in Ann Arbor.

GM and CEO Mary Barra have come under withering criticism from President Donald Trump and politicians in Ohio and Michigan for its decision to end some of its U.S. vehicle production, but GM insists the cuts are necessary to position the business for market changes.

"GM is not basing its production schedule on what looks good. Neither does Nissan," said Brinley. "The decisions these companies have made are not necessarily politically based."

Contact Jamie L. LaReau: 313-222-2149 or jlareau@freepress.com