Differential
 

I've noticed that when I dump the clutch now I'm starting to get a more predominant black line on one side. Does this mean that my limited slip is starting to go? If so, can they be rebuilt? It's the stock unit, and I'm not sure if it has clutches in it or not that can be replaced. Any help out there is very welcome.

clutch packs can be toasted and the life expectancy is reduced with burnouts and donuts.

What tires are you using? I recommend upgrading the rear to 31 spine since your dropping the clutch.

Moser 31 splines and Ford tlok with the carbon clutches is the way to go.