An apparatus for applying and releasing a clutch piston in a clutch cylinder against a return spring includes a fill oil chamber having first and second portions separated by a fill piston. The first portion is in fluid communication with the clutch cylinder through a first passage, and the second portion is in fluid communication with a second passage. A third passage is in fluid communication with the first passage. A fill control valve is operative to alternately communicate the second passage to a transmission line pressure passage or an exhaust passage. The fill control valve is further operative to alternately communicate the third passage to a controllable source of pressurized oil having a signal pressure, or to close the third passage.
