Replace Spindle on JD 62D1 Mower Deck?

[smartc]

I managed to "find" a nice big rock with my mower the other day and seem to have stripped the threads on one of the spindles for my 62D1 mower deck. I have a new spindle to replace it, but for the life of me I can't figure out how to unscrew the spindle from the sheave assembly. All I manage to do is turn the sheave. Checked the owner's manual online and it is not much help.

Anyone have any advice on this?

Thanks!
CS