The United Auto Workers walked off the job at 38 parts distribution facilities belonging to GM and Stellantis.
The strike expansion did not target any additional Ford facilities.
The union president, Shawn Fain, said Ford has made serious progress on a new contract.
While there is more work to do, he said the union won many of its demands.
Ford has agreed to eliminate a two-tier wage structure at some facilities, restore cost of living adjustments suspended since 2009, and provide workers two years salary if they are laid off due to a plant closure.
Fain did not release details about the status of wage negotiations but made it clear these are big wins for his members.
However, the United Auto Workers is now significantly expanding its strike at GM and Stellantis.
Thirty-eight facilities in 20 states started striking at noon Friday. If this lasts long, consumers may see new parts for their vehicles become hard to come by. Fain warned the strike is far from over, including possibly signaling Ford’s Louisville plants as potential targets.
The nearest facility on strike under this expansion is a GM parts center near Cincinnati.
Eighteen thousand workers are now on strike.
The automakers and some suppliers said they have now laid off 6,000 workers because of the strike.