Nut on Front Drive Shaft

So my newly acquired 2001 400 4x4 Big Bear started leaking front differential fluid. I did some reading and discovered that this was not uncommon, and I tore it down and replaced the front seal. Less than a week later, I noticed that it started leaking again. So I did some more reading, and looking at the microfiches online, there are 2 pieces that I think that I am missing. They are parts 19 and possibly 10 from this diagram:
http://www.portyamaha.com/fiche_sect...2001&fveh=1005
Does anyone know what size nut 19 is? I would prefer to pick one up at my local hardware store as opposed to going to my local dealer, waiting a week for them to order it and then overpaying for it.
Also, does the bearing sit inside part 10? or does part 10 sit on the drive shaft side and lock the bearing in place? I remember seeing the bearing, but not part 10.