I've done a Saginaw box without any special tools. Quite a while ago but it's still in service and working. Don't know yours specifically, but I'm under the impression that they're all pretty much the same. It's not a hammer and vise-grip job, but it's not beyond anyone with a bit of skill and patience. The only problem I ran into was having balls drop into the case while installing the worm. The worm will still thread smoothly so you didn't really know one had fallen in.
J.
Edit: I remember I used an old Motor truck repair manual as a reference - it was enough. I could scan the pages and e-mail them if u like.
