Workers in a General Motors auto parts plant in Flint, Michigan went on strike this morning, after making no progress in a 25-hour negotiating session that lasted all night Tuesday. More than 6,800 union workers took to the picket lines, calling for GM to reduce overtime and hire more permanent employees.TIME Detroit bureau chief Bill McWhirterdescribes the latest walkout as a "virtual replay" of last October's strike at another Flint plant, when GM reluctantly gave in to the strikers' demands for a staff increase. McWhirter says that GM's current hard stance is surprising. "By giving in last October GM made it hard to say 'no' to the same issues. The only difference this time around is that because of interest rates there has been some softness in customer demand that was not there this past fall." The strike could quickly cripple American car production, as the Big Three automakers and numerous repair shops rely on the Flint plant for such parts as spark plugs and air filters.