couple HM-284 questions

[pwmin]

my tranny is leaking, so i think im going to have to pull it apart and reseal it.
1) there is a leak coming from the bolt being pointed out with a black arrow. it is not tight, but when i turn it, it feels like it has some weight to it and wont tighten. is there a nut or something on the other side or is it supposed to be like that
2) i was told that if i tear it apart and something happens to the seal in the part pointed out by a red arrow, i will not be able to find a new one to replace it with. is this true, and if so, what is he talking about and does anyone have the part i will need.
3) what is the easiest way to reseal it. im assuming ill have to pull it? and is there anything i should do while i have it apart.

seems like i have some stupid questions, but dont worry, it will get put back together correctly. i just havent ever had one of these manuals apart.

here is the pic:

[pwmin]

could someone at least tell me what the hell the black arrow is pointing to and if it should be tight? i pulled the parts blow up off of alldata but couldnt exactly see what i was looking for.

[pwmin]

okay, so i finally figured it out except for question 1. probably going to pull it tomorrow. luckily, i have till next thurs off.

[pwmin]

well, apparantly it needs to be tight. had to tear the whole damn thing apart, but at least i got to make sure everything was still kosher. getting ready to put it back in. had a fun time trying to find axle seals. dealer had to order some but they wont be here till friday (discontinued, of course). got lucky and found a couple that would work that my dads shop had laying around.