rear driveshaft/axle leak

["Bryan Gillespie" <gillespie@domain.elided>]

I've got a leak where the driveshaft meets the differential casing (is that
what you are calling the pumpkin?) on my rear axle ('70 800A).  I've never
done any kind of work like this before now and I've got some questions.

1. what kind of oil goes in the "pumpkin"?

2. am I going to have to completely remove the rear axle
(wheels->drums->axle) from the driveshaft to get to the seal (if that's the
culprit?

3. somewhat related, please look at the picture of my 800A on my website
(http://www.krusty-motorsports.com/scout).  It seems that my rear axle sits
about 1"- 1 1/2" too far back in the wheel well.  I'm wondering if the rear
axle has slipped back and that's part of the cause of the leak.  I know that
sounds really far-fetched, but I am on planning on putting 31x10.50s on
soon, and would like to have them centered in the wheel well (otherwise, I
think they would rub constantly).

4. finally, i'm probably the definition of novice, so any helpful tips with
this project would be greatly appreciated.

Millions of thanks in advance,

Bryan Gillespie