Pulled off the black plastic cover at the base of the windshield.
Found the motor was driving the arms through two little ball joints that the
driver/connecting rods were attached to.
Balls were shiny and dry, so I loosened the binder bolts on the assemblies that
ride on the balls, slathered everything in grease, closed it up and no more
But in retrospect, that assembly looked like it was crying out for nylon
bushings between the balls and the assemblies that rode on them.
Should there have been bushings in there?