[dwcsr]

Not sure on what you mean by carrier pin, and when you say slop in the pinion do you mean up and down or back lash? The rear is a stock GM rear for that year. Parts are hard to find new or NOS, You may need to find another good rear to fix what you have.

You need to look at the axle shaft bearing surfaces, If it was leaking badly then the surfaces are most likely very pitted and you will need axles as well.