The viscosity should be low enough to withstand the greatest anticipated torque load and low enough to minimize power losses.

The viscosity should be high enough to withstand the greatest anticipated torque load and high enough to minimize power losses.

The viscosity should be high enough to withstand the greatest anticipated torque load, but the viscosity should be low enough to minimize power losses.

The viscosity should be low enough to withstand the greatest anticipated torque load, but the viscosity should be high enough to minimize power losses.