Castrol Axle Z Limited Slip 90 is a mineral oil-based transmission oil suitable for use in limited slip differentials (blocks) of passenger cars and heavy vehicles that require an API GL-5 grade oil with special limited slip tribological performance characteristics. It can also be used in conventional differentials. It is approved by ZF for use in multi-disc wet brake and self-locking differential systems widely used in heavy-duty applications, including earthmoving and agricultural machinery axles.