heres a vid of how to change it, its so easy, just wear latex gloves when you do it, the old oil stinks bad, and will stay with you for a while if you get it on your hands, get some brake cleaner and clean the inside of everything with it, dry it up and slap it back together.
YouTube - ‪Replacing a worn out supercharger coupler on 3.8 GM engines‬‏
EDIT: quick tip on latex gloves, wear 3 pairs at a time, they always tear.