In the United StatesWork has been stopped at three plants owned by General Motors (GM), Ford and Stellantis.
The move came after labour contracts expired on Thursday night and the United Autoworkers Union (UAW) said the firms had not put forward acceptable offers.
The strike started at midnight eastern time (04:00 GMT) at GM’s Wentzville, Missouri mid-size truck plant, Ford’s Bronco plant in Michigan and the Jeep plant in Toledo, Ohio owned by Stellantis.
The plants are critical to the production of some of the “Detroit Three’s” most profitable vehicles.
The fight threatens to trigger higher prices for buyers and major disruption for the motor industry giants but UAW’s president Shawn Fain told the News correspondents it was now up to the companies to resolve the dispute.
The UAW however said other facilities will continue to operate, but it did not rule out broadening the strikes beyond the initial three targets.
With the deadline looming on Thursday, the White House said that President Joe Biden had spoken on the phone with Mr Fain about the negotiations but provided no further details.
The union had sought a 40% pay increase for its roughly 140,000 members over four years, noting a comparable rise in pay for company leaders.
Other demands included: A four-day working week, the return of automatic pay increases tied to inflation, stricter limits on how long workers can be considered temporary staff who do not receive union benefits.
The UAW’s proposals would more than double its US labour costs, Ford said in a statement.
Last month, 97% of the union’s members voted to authorise a strike with Workers insisting the companies could afford to be more generous after years of record profits.