Abstract: A hydrokinetic torque converter is provided with a lockup clutch wherein the piston and other constituents of the lockup clutch are adequately cooled during each stage of operation of the torque converter and its clutch. The piston of the lockup clutch and/or the component which cooperates with the piston to transmit torque from the housing directly to the turbine of the torque converter is provided with a friction lining which establishes a portion of the path for the flow of fluid coolant between the fluid-filled compartments at opposite sides of the piston. The rate of fluid flow between the compartments is regulated by one or more adjustable valves which are carried by the housing of the torque converter and/or by the piston of the lockup clutch.