5.2 Magnum fan clutch

Usually do it with the belt still attached to hold pulley, but have done it in a vise as well. If you can get the proper size wrench and a plastic dead blow mallet, give the wrench a few good blows to loosen clutch nut, hopefully it will come loose for you. if it doesn't, there is a special tool attachment that goes on an air hammer that a local garage should have, ask nicely and they should be able to help you out.