As perhaps you'll be able to glean from the pics, it's a 12-bolt rear end. If you'll allow me my very lame-man's summary of the situation, I took off the cover to see what the heck is inside the big part. Then, with some effort due to rust adhesion I guess, I removed the drums. A co-worker advised me to see if both axles turned in the same direction, while turning the yoke (?). Indeed they do, but it looks like a pin of some kind might be missing, and a bolt or two. Anybody have a reference resource on how to get this sort of thing sorted out, or would I be smart just to bring it to a transmission place and let them bust their knuckes?

Lastly, there looks to be a patch on the axle tube on the right side. Is this a fairly common thing, or do I maybe have a pig in a poke?

http://i31.photobucket.com/albums/c351/Nate1776/12bolt021.jpg
http://i31.photobucket.com/albums/c351/Nate1776/12bolt026.jpg
http://i31.photobucket.com/albums/c351/Nate1776/12bolt027.jpg
http://i31.photobucket.com/albums/c351/Nate1776/12bolt028.jpg
http://i31.photobucket.com/albums/c351/Nate1776/12bolt054.jpg
http://i31.photobucket.com/albums/c351/Nate1776/12bolt022.jpg

posi yes

The spider shaft and (hopefully all of) the retaining bolt do appear to be gone.
Also, one of the c-clips that retains the axles is not visible in the picture, it is likely floating around inside there somewheres.

Yes, that is a posi.

I won't worry too much about the "patch," yet. Unusual yes, unheard of, not really. These things are old. If it's straight, and doesn't leak, it will be fine.

You'll for sure want to go through it and make sure everything is right.

Wonder why the pinion shaft is gone?
Very likely there was a problem with it, someone did an inspection, decided not to hassle with it, and then didn't reassemble completely before selling it. Was the cover sealled up tight, or just loosely reinstalled?

Yep, Limited slip posi-traction.
(a non-posi doesn't have those springs or the extra gear)..
A Detroit locker has teeth meshing instead of a spring pack..

The patch on the end looks like someone cut off a bracket,
and I'm guessing they welding on the leaf-spring perch.

I would find a local driveline shop.
Call some transmission places and ask them who they recommend.
Take it to them as is, ask for an inspection and recommendations, should be no charge.
What was this out of?

also in second pic there is somme rust on the ring gear. that may also need to be replaced. guessing there was no oil in it from sitting there.

You gottom 3 series carrier, with a spacer too.

Are you sure? It looks like it could be a 2 series with a spacer.

Uh, what does a 3 series or 2 series mean, to us newbies? :)

Also, would Summit be a good source to obtain the missing parts (the spider shaft and the retaining bolt and C clip for one of the axles)? Jim, as to the pinion shaft, I don't think it's missing, if by pinion shaft you mean the thing that connects the yoke to the pinion.

Lastly, here are some more pictures which I took last night. Presuming the gears inside the (posi) spring loaded gizmo don't factor into the equation, I think I have a 3:73 setup. 41 teeth on the ring, and 11 on the pinion, which works out to 3.727, right?

http://i31.photobucket.com/albums/c351/Nate1776/12boltparttwo003.jpg
http://i31.photobucket.com/albums/c351/Nate1776/12boltparttwo010.jpg
http://i31.photobucket.com/albums/c351/Nate1776/12boltparttwo011.jpg
http://i31.photobucket.com/albums/c351/Nate1776/12boltparttwo012.jpg
http://i31.photobucket.com/albums/c351/Nate1776/12boltparttwo013.jpg

Sorry, I meant the spider shaft, the one that goes thru the center of the carrier.

The series is what gear ratios will bolt to the carrier. If you have 3.xx:1 gears with a spacer you have a 2 series carrier. Unless you have the tools (press and dial gauge as well as large sockets) and the knowledge to setup a rearend properly I recomend finding a local rearend shop. They will have everything needed including the missing parts. They will also be able to tell you if that patch messed up the axle tube or not.