If you are hearing a rattling sound from the Supercharger you dont have to replace it.There is a Coupler in the nose of it that can be replaced and if you
Click Here there are instructions for replacing it.Also a site called ZZPerformance sells one better then the factory Eaton Coupler.
Click Here for replacment coupler and
click here for GM supercharger oil and you will need 2 bottles of GM supercharger oil when replacing the coupler.
Hope that helps save you some money.
~Larry~