Plastic gear in agitator was worn. Note that this plastic part is typically hidden by a metal insert that converts the diameter of the shaft gear to the diameter of the agitator (pulsator). If you can spin the agitator freely, check here first before concerning yourself with the actual motor/gearing under the unit. All you need for this repair is a flat blade screw driver to pop the cap off, and a 10mm socket to pull the agitator (pulsator). My cap broke so I replaced it, but you might have better luck getting yours off and only need the agitator/pulsator.