You need a fan clutch removal tool like other members have showed. IMO I would not hammer or hit the shaft as you will prob damage or bend the water shaft. Goodluck.

 

i didnt damage mine and the threads were normal on my 97 4.6L the hammer and punch took all of 10 mins for me and it came right off...then i kicked the crap out of my clutch fan!! i didnt use a rachet to hold the water pump i put the belt back on and my tension held it in place

 

That is why I didn't want to do that. I know it works and other local mechanics have said it will work. I just didn't want to take a chisel to my new truck...LOL

And the threads are not reversed, I wish people wouldn't say that, it can really cause confusion for people.