Motor runs, but beater doesn't turn

Question

My KitchenAid is 15 years old and I am about 300 miles from a repair shop. Is there any way to find a schematic so I can attempt to repair my mixer?The motor runs strong, but it no longer turns any attachment. I am guessing a gear has finally worn out, but I cannot figure out how to open the casing or how to find the challenged piece. Is there a way to get a schematic to see if this is fixable before I buy another?