A clutch shift modulation system is disclosed in operative relationship with a transmission having a torque input shaft and a torque receiving shaft. The transmission includes fluid pressure engaged forward and reverse clutches that may be engaged to drivingly rotate the receiving shaft in the respective forward or reverse direction when acted upon by fluid at a selected pressure, and a pump driven by the input shaft is adapted to supply fluid at this pressure to a shift valve which may be moved to a forward or reverse position to selectively connect the pump with the respective clutch through suitable conduits. A reversible pump driven by the receiving shaft pumps fluid in a direction and at a pressure which is a function of the rotative direction and speed of the receiving shaft and this reversible pump is connected between the two conduits leading from the valve to the two clutches so that during shifting it detracts from the efforts of the input driven pump to engage a particular clutch until the rotation of the receiving shaft in the respective opposite direction has slowed to below a selected speed and thereafter aids in the efforts of the input driven pump to engage this clutch.