Product review (2 stars): Shaft bore hole out of tolerance - undersize .005", and wouldn't fit.
Main shaft hole was out of tolerance undersize 5-thousandths of an inch and would not fit without machining. Original part bore diameter was .626" while new part varied from  .620" to .621". The washer's transmission gear shift shaft where the Wig-Wag Solenoid fits is .625" or 5/8".

An install tip or two... a little penetrating oil in the bolt hole and on the end of the shaft goes a long way to getting the Wig-Wag Solenoid loose. Before installing the new part, cleaning the shaft with some 400 grit emery paper or Scotch-Bright, followed by a dab of oil helps the new part (with the correct hole size) go back on.

Also worth noting for those try to diagnose a potentially failing Wig-Wag Solenoid, the correct resistance of each coil is about 545 ohms as measured with a Fluke model 85-III multi-meter. Both coils on my old part had failed and had infinity resistance.