5.2 Magnum fan clutch

I used a large cresent wrench on mine, and had to borrow one that was also thin enough to fit in the tight space where the nut is. Just as people have said above, it just takes a good whack. I was actually surprised how that's all it takes. I was the confused the same as you and my dad helped me out here.

Same with going back on you just give a good whack back in the other direction, not really tightened like you might think. I guess it's because of the LH threads and will only tighten when the motor is spinning.