Whirlpool Thin Twin Agitator help

I have a Whirlpool Thin Twin 24" stacked washer-dryer. The top assembly of the agitator is slipping off easily, exposing the bolt - there is nothing keeping it anchored to the center hub. I didn’t see any pieces of plastic or other parts break off in the load of laundry. How can I reattach the top assembly to the main hub of the agitator?
Thanks!

May I please have your model number so I am able to provide you with accurate, model specific information?

Lte5243dqa

Thank you, so number 3 is off and floating?
APP1.jpg (24.6 KB)

Yes, with #1 still attached to it. When I set it back down on the agitator, it will catch and rotate appropriately, but it slides up and down on the central post with nothing preventing it from coming off when the machine is working. I just can’t figure out how it’s supposed to attach and remain in place. Thanks.

The bolt keeps it in place, it is worn and will need to be replaced. That part is available below.

Whirlpool 63840 Filter (upper Agitator) - AppliancePartsPros.com

Thank you! Will get it and update.

You are very welcome! That is a 7/16" bolt I believe and the new agitator part will slip down over the bottom and the bolt will secure them both. Have a great afternoon!