Hapco Limited Slip Additive effectively reduces wear, noise and chatter in differentials. Our formula helps provide extreme pressure-wear resistance in any fluid system. Will not harm seals and does not contain petroleum distillates. For Best Results: Add one 4 oz. bottle of Limited Slip Additive when gear oil is changed or unusual slip is detected. Drive vehicle as normal to allow circulation of fluids. Also safe for: electric motors, hydraulic pumps, moving shafts, power mowers and pillow blocks.