Aaron, I watched your video on the steering box and found it so good I bought a whole new unit already put together.

That was our secret plan- make it look so complicated everyone would just buy a complete gearbox
My problem is with the Pitman arm.
Yup. Unfortunately, that will be one of the hardest parts of the job even if you get the complete new box. My only suggestion (and what we do here).... a good puller,
lots of pressure on it, and then large amounts of heat on the pitman arm splines very fast. You need a torch (preferably an Oxy Acetylene setup but a cheap Butane soldering torch will work too) and try to get the pitman arm almost red hot so it expands before the shaft gets hot and expands too. It may take several hot/cool cycles to get it off.