Abstract: A clutch having a rotating input member, a rotating output member, an annular cylinder on the input member, an annular piston in the cylinder defining therewith an apply pressure chamber on one side of the piston, a balance chamber on the opposite side of the piston filled with fluid when the apply pressure chamber is filled with fluid so that centrifugal force components of the fluids in the two chambers are balanced on the piston, and a valve on the input member biased by a spring to a closed position closing an exhaust passage from the balance chamber and exposed to pressure in the apply pressure chamber, the spring being calibrated to maintain the valve in its closed position against apply pressure until apply pressure achieves a magnitude corresponding to full clutch application whereupon the valve shifts to an open position allowing the balance chamber to exhaust so that the centrifugal pressure component of fluid in the apply pressure chamber is unbalanced to increase the torque capacity of the clutch.