Fill to the hole. Lucas says it is ready for limited slip, but that would be my last choice. Advance Auto is in Chesapeake. See if they have Valvoline or Castrol 80W-90with LS additive already blended in. The stores near me have it. Try that first. If you get clutch chatter out of your rear end, add a very small amount of additive. Like 1/2 an ounce. This is a case of where the right amount is necessary, but too much is no good.
