Maytag washer

The agitator won’t stay down! I can pull it straight out. I have located the screw at the bottom of the agitator that disconnects the plastic from the steel shaft. Do I need a retaining clip of some kind to keep the shaft in the tub?

I am having this exact same problem. The agitator shaft pulls straight up and out along with the agitator (plastic part). Can anyone shed some light on this? Model LAT9406AAE.

Thanks,
Scott