There is a special tool that you can borrow from Autozone to remove the fan clutch. The tool looks like a very wide wrench and it fits over the bolts on the pully to hold the pully still as you loosen the big bolt. If you don't have an autozone nearby, the tool usually costs about $20.
i did this job just this week on the 4.7.i also had the clutch go bad. get a bolt that fits inside the blank holes on the pulley for the water pump.next you'll need a large screwdrriver wedge it between the bolt and the pump shaft.at htis point a friend could come in handy. next put a wrench on the clutch nut. i used a ford wrench.but an adjustable will do.break loose while you keep tension on the screw driver. the fan to clutch bolts are 13mm. if all go well like mine did you should be done in about 20 min.if you run into trouble pep boys will replace it for 51 dollars.hope this helps
I baught a strap wrench for that purpose but ended up not needing it. I got the old fan off by wedging box wrench between the pully and belt. That put enough tension on the pully to break the nut free. Thanks for all the advice!