Abstract: The time rate at which pressure increases in a friction element engaged to produce a gear shift is controlled through operation of an accumulator. Shift valves in a hydraulic circuit produce selectively a connection between hydraulic lines associated with the friction elements to be engaged and a source of line pressure. A first control pressure has a magnitude that varies according to a required torque transmitting capacity of the friction element. A line modulator valve produces a second control pressure having a magnitude that varies with the magnitude of the first control pressure but at a different rate. An accumulator includes a piston movable within a cylinder defining a first volume connected to the second control pressure output by the line modulator valve, and a first volume communicating with line pressure.