Have you seen the thread over on Pirate? i believe i put it on the Planet a little while ago. Im not on my normal computer, so i dont have my favorites list on here, but a quick search or "Aisin Hub Rebuild" on google should bring it up to the top. They are really very simple, and there isnt much that can be put together incorrectly. About the only thing that can go wrong is one of the springs isnt sitting right on the clutch pawl, and that can lead to the hub not disengaging (or engaging in the first place, for that matter.) correctly.
Also, if you find that you do need some of those spacers, contact matt at Indy4x. He has some, and can hook you up well. The way he explained it to me, some of the hubs had those spacers, some of them didnt. Yours needs it, for whatever reason. I wouldnt put them on my truck without one on there.
-J <img src="/forums/images/graemlins/kewl.gif" alt="" />