The UAW is pushing back against GM's announcement to idle up to 5 plants, including two in Michigan.
The move would cost thousands of people their jobs.
The UAW's Vice President and Director of the Union's GM Department sent a letter to the automaker Monday. The letter asks GM to rescind its decision.
That letter claims GM violated commitments during 2015 contract bargaining talks.
The letter says those details can't be discussed.
GM is set to lay off workers at the Detroit-Hamtramck assembly plant, the Warren transmission plant, as well as plants in Ohio, Maryland and Canada.
GM has said many of the workers impacted by these actions will have an opportunity to shift to other plants.
In a response to GM, the UAW's President says "The UAW will leave no stone un-turned and use any and all resources available regarding the future of these plants... The UAW members and US taxpayers invested in General Motors during their darkest days...now it's time for them to invest in us."
The layoffs are GM's response to falling sales of sedans and compact cars.
They're expected to take effect by the end of 2020.
Meanwhile Ohio's two Senators say they'll meet with GM CEO Mary Barra Wednesday in Washington to figure out what can be done to stop the Lordstown plant from closing.
Senators Rob Portman and Sherrod Brown say they've given GM proposals to help save the plant, where about 1500 people work.
