Patent ID: 7487865
Filing Date: 2009-02-10
Classification: F16H

Abstract:
1. A method of controlling a torque-transmitting mechanism in a multi-speed transmission, the torque-transmitting mechanism being engagable via an apply piston having an apply surface and an opposing reaction surface, the torque-transmitting mechanism being engaged during two speed ratios, the method comprising: positioning a dam member axially with respect to the apply piston such that the reaction surface of the apply piston and the dam member substantially form a reaction chamber and the apply piston moves axially with respect to the dam member when the torque-transmitting mechanism is engaged via the apply piston; establishing a first reaction pressure at the reaction surface during engagement of the torque-transmitting mechanism to establish a first of said two speed ratios; and establishing a second reaction pressure at the reaction surface during engagement of the torque-transmitting mechanism to establish a second of said two speed ratios, thereby permitting greater control of the torque-transmitting mechanism in establishing different respective torque capacities of the torque-transmitting mechanism in the respective speed ratios.