If I remember correctly from when I built mine last winter, I just drove it out with a big flat head screwdriver or round punch and a hammer. Kept tapping on opposite sides unlit it worked its way out. I put the new one in with a bushing/bearing driver kit I had from harbor freight.
Have to take the extension housing off to do it and don't forget a new extension housing gasket and output seal. I think that was the easiest bushing to replace in the trans.
Worst comes to worst you can always bring the extension housing and new bushing and seal to a ford dealer or machine shop and pay a few $ for them to do it for you.
