What to know about the UAW's historic labor strike

STORY: Negotiations between the United Auto Workers union and the so-called "Big Three" Detroit car manufacturers are set to continue over the weekend, as the two sides continue their face off in the largest American labor action in decades.

12,700 UAW members stopped working Friday at three factories belonging to General Motors, Ford Motor, and Chrysler's parent company Stellantis.

This was the UAW's leader, Shawn Fain:

"Well I feel damn good. I'm damn proud to stand here with the VP of the UAW Ford, the top AA and all of our workers out here. These guys are the ones, this is what it's all about."

REPORTER: "Any message to your members out here tonight? What's the final message before you head home?"

"Record profits, equal record contracts. It's our time, and all we want is our share of equity. We're not asking to be millionaires."

It's a line that was repeated by President Biden hours later, that record profits at car manufacturers should mean record contracts for their workers, and he said that while the companies have made significant offers they didn't go far enough.

The UAW is the only major union which has not endorsed Biden's re-election campaign, with many members in important swing states. The U.S. government has been pouring billions of dollars into subsidies for electric vehicles, but electric vehicles require fewer jobs to make them.

Meanwhile, the UAW is holding off on widening the strikes to other factories or entire companies... for now.

Central to its demands is the end of what it calls a "two-tier" system for workers, where workers on the lower tier can make only half the hourly wages of more senior members, and take a longer time to reach that higher level.

This worker was on a picket line in Wayne, Michigan:

"You know, I just started a month ago, and I'm making like 16 bucks an hour and it's beating me up. So I can't imagine what these people who’ve been working 25 years -- it's a lot, it's a lot. I should be making the same as as my coworker."

None of the car companies have proposed eliminating the tiered system.

Stellantis also said Friday that it's gone into what it calls "contingency mode" and that it will make structural decisions to protect itself, without elaborating.

Fain said earlier this week that Stellantis had proposed shutting up to 18 facilities in the U.S.