Limited Slip Differentials - Just Differentials At Just Differentials we stock the top limited slip style differentials from all the top manufacturers. A limited slip differential uses clutches, cones, or helical gears and pre-load to prevent wheel spin. They increase traction significantly, are smooth on the street, reasonably priced, but never will be 100% locked. Limited Slip Differentials Eaton Truetrac The Truetrac uses helical type 'worm' gears. These gears are directional by design and fit specifically in either a front or rear application. Does not require a friction modifier or synthetic oil. Does not 'chatter' or make noise like a clutch style limited-slip. Auburn Limited-Slip Differential: Uses clutch-cones instead of clutch disks. 2 pinion design. Not rebuildable, 1 year warranty + 4 Year replacement plan. Requires friction modifier. Eaton Posi: Carbon fiber clutches, not steel. Rebuildable, optional coil spring preloads 200-800 lbs. Requires friction modifier. Nitro Power Lock: 4 pinion design. Rebuildable clutches, no clutch guides. Aggressive traction profile. Requires friction modifier. Eaton Trac Loc: Lower initial purchase point. Rebuildable clutches. Requires friction modifier. Nitro Posi: Carbon fiber clutches, not steel. Rebuildable, uses Eaton springs. Requires friction modifier.