2004 Ford Taurus Thumping noise in front end

2004 Ford Taurus 6 cyl Automatic 57400 miles

I hear a thumping/thud noise when I drive especially noticable at slower speeds. It seems like its coming from the driver side tire area, but not sure. I have put on new tires, balance, rotate, alignment and ball joints replaced. Had the shocks and strust check and was told they are fine. Any ideas what it might be? Im going out of town and am worried about breaking down.