I replaced my XE ps pitman arm with two different types, and I don't use ANY special tools bar these two:-
1. A big steel crow bar 6 ft long, hexanagonal section, and with a large wedged end on it. It weighs 30 pounds!
2. Disc grinder (small 75mm, with a cage so that my fingers don't get sliced off!)
The safe procedure for this was to firstly take the bolt off the pitman arm, pour CRC, penetrating oil, siliva and incantations acording to you faith on it, and then open the bonnet and gently belt the top of the pitman arm with that heavy bar. Poor begger if you have an EFI or V8. If, after 5 minutes of stress free belting it doesn't come free, then use the disc to gently ring bark the arm falcrum to well before the spline. Add more CRC, then it should break free with some gentle smacks. Lotsa fun if your patient. Your mates think your a bit strange, but I still have fingers and a removed Pitman!
PS... don't use Tiwanese pitman arms. Some are indexed 1/8 of a turn out, and have hopeless quality control. Mine had more slack after changing it that the Inspection Authority gave my vehicle a defect notice AFTER I added a new one. Yeh, it was torqued up to spec!