A torque transfer mechanism for controlling the magnitude of a clutch engagement force exerted on a clutch pack that is operably disposed between a first rotary member and a second rotary member includes an actuator having an inner sleeve, an outer sleeve, and a plurality of balls. The inner sleeve is supported for rotation relative to the first rotary member and each of the inner and outer sleeves includes a spiral groove aligned with the other. The balls are positioned within the spiral grooves between the inner and outer sleeves. An electric motor selectively rotates one of the inner and outer sleeves so as to induce axial movement of the other of the inner and outer sleeves to engage the clutch.