In the past I've had a lot of trouble replacing fan clutches. Having the right tools is of paramount importance. A 3473 wrench and this 3900 pulley holder made it possible to change the fan clutch on my 2000 F350 to 7.3 in no time. I used a 1/2" ratchet on the wrench for a little extra leverage. It was the original fan clutch, so the mother was 19 years and 235,000 miles on it. The whole repair didn't take long.