The first challenge I encountered was the removal of the agitator from the tub. I was able to get the cap and rubber gasket from the top of the agitator, however I could not remove the agitator from the shaft. It would not lift off with as much persuasion as I dared to apply. The top of the agitator appears to have a square hole to match a square section on the shaft. The square section of the shaft appears to have shifted in the square hole so that the points of the square are imbedded in the flats of the plastic. How can I remove the agitator without damaging it?