I watched a short 3 min vid on you tube a guy changed out a coupler I really think that sounds like what it is... I think the pulley did not spin when I took the belt off but it was dark, cold, late and I felt like it was mission impossible in that parking lot last night lol so I cant say for sure .. Gonna check it in the morning Replacing a worn out supercharger coupler on 3.8 GM engines - YouTube