Help me diagnose this!!

[tucsonjwt]

I am about like you (except a factor of 3x older) and I would not do the rebuild myself, without a skilled adviser present.
I do have a 3/4 ton floater but I had lots of trouble with axle seals (properly called wheel seals) until I searched the web and found out the GM came out with new two piece seals to replace the one piece seals they used to have. Even my professional axle mechanic did not know that, and I went through two sets of seals until we put the new style in - ruined rear brake shoes and drums in the process. I mention this just to show how little issues like this are likely to ruin a repair effort when it comes to rear axles.
Having said this, I have never had any other issues with my other two 3/4 ton squares, so I guess floaters are more reliable than the 1/2 ton axles, but they are way heavier and don't help your gas mileage.