ST. LOUIS (AP) -- Workers at the General Motors plant in the St. Louis-area town of Wentzville are going back to work starting Monday.

  The plant will restart after being shut down since March 6 due to a parts shortage caused by a strike at a supplier, American Axle and Manufacturing Holdings in Detroit.

  First-shift employees are due back at work Monday. Third-shift parts stamping workers return May 18. Second shift assembly workers return May 19.

  GM spokesman Dan Flores says the company found another source for the parts. He declined to elaborate.

  United Auto Workers Local 2250 chairman Bill Schiltz says union leaders are concerned about where those parts are coming from.

  GM makes full-size vans at Wentzville, and employs about 2,300 UAW workers there.