The easiest LSD to use is one designed for the early AE86. The OEM LSD is not that good, and probably worn out now. Get a TRD one as I have. You may have to grind 1 or 5mm off each axle depending on what denter you use. You can buy the TRD one new, but its cheaper to get one second hand, as a import from Japan. Mosty they are in OK condition.