• Olefin copolymer VII
• Highly shear stable
• Can replace PIB and high-viscosity synthetic base stocks in high-load applications
• No diluent oil

Some viscosity modifier polymers do not have sufficient shear stability to handle highly loaded gear applications, resulting in poor lubricant performance and shorter fluid life. Formulators will sometimes use polyisobutylene (PIB) to thicken oil, but this can be difficult to handle, pump, and blend. Polyalphaolefin (PAO) oil is also commonly added to axle fluid formulations, but this synthetic oil is expensive, driving up the final fluid cost and making it difficult for oil marketers to be competitive in the service fill market.