I have had luck in the past by heating the area around the threads a little then pouring WD-40 around it. As the metal cools it draws the oil in which helps getting the pulley off. Half the battle is holding the wobble box securly while trying to turn the pulley. I finally cut some holes in a large metal table in the shop so I could bolt the box down to work on it. That helped more than anything else I ever tried. Unless you are really lucky you will need a really loooong cheater pipe or a big impact wrench. Good luck