Vintage Oster 403 blender help

[Eric H]

I just looked at mine, I believe the metal flange is just pressed on, it should pry off with a couple screwdrivers (with some padding to protect the case), after that's off I think the rest of the drive will fit through the hole.

I saw that screw in square drive, I'm not sure the original old models had that or if they are one piece.