your definately going to want to use a puller. put some pressure on it and tap it with a hammer and the thing should fall right off. if u cant get ahold of a puller you may be able to put some pressure on it with a pry bar and give it a few good taps with a hammer.

 

I used the puller from autozone and had to grind it a little to make it fit. My first attempt didn't go so well, maybe I overheated it or ground off too much but when I started to put a lot of torque on it one of the arms snapped off. They are just a cheap cast material. On my second attempt I was more carefull and only ground off the minimum needed for it to fit. The pitman arm doesn't slide off like you think it would, it actually pops off with some force.

Bill