Provided the diff side bearings are ok, you start with a simple test. When turning one output shaft, does the other one turn the same direction? If it turns the other way, you will need the complete LSD setting procedure. If it turns in the same direction, go to next step: how much torque you need to apply to turn one flange when the other is kept stationary. A std new LSD will turn with ~10-11lbft, and much less if thoroughly worn. Re-tightening to spec requires disassembly and switching to thicker cross-plates -if available- or adding suitable very thin spacer washers (possibly an assortment from 0.1-0,5mm). If you have the 4-cyl or V6 book read how its done. If not and you haven't done this before, find someone competent to help you out.