The thread is left hand; from the front of the engine you turn the wrench to the right (toward the driver side). Do this when the engine is cool.
Some people pull the entire fan/hub assembly out past the radiator shroud, others remove the fan first, then remove the hub.
In many cases, a drift punch and hammer are are the easiest tools to use for breaking the nut loose - place the punch on the driver side of the fan nut face and hit the punch with a hammer. When the nut has been loosened, it can be removed by hand or with a pair of channel lock pliers. One person reported that an air chisel quickly loosened the nut.
To remove fan drive assembly with a wrench, use 36mm or 1 7/16" wrench (some use a 1 1/2" wrench). You may need to whack the wrench with a hammer to break the nut loose. The fan hub can be held with channel lock pliers or you can use a 3/8" breaker bar on the belt tensioner to tighten the belt.
Once the nut breaks loose, you can unscrew it by hand and pull it out the top while pushing the upper radiator hose out of the way.
Store the fan upright so the oil doesn't come out.
To replace the fan, hand tighten the nut with channel locks. The engine will torque the nut.