I was reading through some older posts and saw this one.
Just in case someone is needing to replace their radiator fan clutch: When I did this on my 1995 F250 PSD, I went to O'Reilly Auto Parts and rented a fan clutch wrench kit (seems like it was $75 or so, put it on a credit card, then they credit the charge when you return the tool), and ordered the fan clutch from RockAuto.com. Initially, I ordered the Motorcraft clutch, listed for $287.79 this past April (2012), but they called me and said they were out of stock. So, I went with the Four Seasons brand for $161.79. With the tool kit, it was a breeze to install, and it made a big difference in my A/C temperature. The old clutch wasn't working properly, thus not pulling enough air across the A/C condenser (high-side A/C pressure was going WAYYY too high, would drop immediately if I sprayed water from the garden hose on the condenser.) For reference, my fan clutch had a "normal" thread to spin on to the water pump shaft: counter-clockwise off, clockwise on.
P.S.: I have used RockAuto for lots of parts purchases that I didn't need immediately. Sometimes, their "standard" shipping showed up at my door in two days. Otherwise, it was 3 or 4 days, depending on where it was being shipped from. And, their customer service has been outstanding! One time, I ordered an ATP in-line transmission fluid filter kit. When it arrived, it was missing 3 of the 4 hose clamps that were supposed to be in the box. I called them about it, and they sent an entire new filter kit to me, free of charge! So, I have a new one on the shelf for the next time I need to change that filter. They are tops on my list!