Driveline Fluids Comprising API Group II Base Oil

Described herein is a process, comprising: a) selecting an API Group II base stock with selected viscosity index and pour point; b) blending a base oil with the base stock, and c) adding to the base oil: i) a liquid ethylene propylene copolymer viscosity modifier that reduces a traction coefficient, and ii) an additive package, to make a driveline fluid that has a defined viscosity index and excellent shear stability. Also provided is a driveline fluid composition having the high viscosity index and excellent shear stability, comprising: a) a base oil comprising from 50 wt % to 100 wt % API Group II base stock; b) a liquid ethylene propylene copolymer viscosity modifier that reduces a traction coefficient; and c) an additive package. Further provided is a method for lubricating an axle or manual transmission by supplying the driveline fluid composition.