I have a 8" diff for sale, it has 2.79 open gears and 28 splines. It is in excellent condition. I am not asking alot for the diff. I do not know if you would be interested in this diff it has the retainer plate inside. If interested please PM or e-mail me and I will give you asking price
if its that far gone I suggest a new 3rd member as that one probably has excessive wear on the gears and/or case etc....maybe its time for that upgrade to better ratio and a posi if you don't already have one.