Oh! So, the green cup isn't part of the CV halfshaft! It's the "receiver" where you slide the CV axle into!?!?!
Somehow, I was picturing the inner green cup as being ON the CV axle. I thought it must be the inner "bulge" on the CV unit. IOW, I kinda thought you were talking about the non-accordian inner rubber sleeve/protector that's held on by bands.
Cup sounded more like rubber than metal.
Now that I understand that, I assume the CV axle simply slides in the cup -- which sits at the outer end of the axle housing. How often do people worry about pulling the outer axle bearing for replacement or service?