Looky what I found!

Never seen that one before.
Usually they get more busted up than this when you have those
Kerchunk sounds.
In the old days it was simplest to go to the salvage yard and buy a complete replacement
rear axle assembly and you were back on the road pretty cheap and fast.
Today since the parts arn't easy to find in the yards anymore it may be best to take the time to clean all the metal out of the housing and rebuild what you have.
If you had plans of ever swapping to a different rear such as the 8 3/4 or Dana, looks like
it may be the time.