Tray answered your WD40 question.

I've done about half dozen steering installs....Xrock's Xterra was the worst one to get the pitman arm off...we fought that one. Mine were both pretty easy.

The 3 jaw puller from Autozone is what you need....don't get the little 2 jaw one - it's not big enough. I use that tool enough that I just bought one from them.