Abstract: A vehicle drive system includes a torque converter interconnecting an engine and a speed change gear and a flow brake is drivingly positioned between the torque converter and the speed change gear. A rotor of the flow brake is driven from a drive train which includes a torque converter turbine and the primary side of the speed change gear. During a braking cycle, the speed change gear is downshifted by one or more steps to increase the rotational speed of the flow brake rotor and generate a high braking moment. Because of high rotor speed, the flow brake is relatively small. The torque converter includes a bypass clutch which is disengaged during braking to permit negative slip in the torque converter and prevent excessive engine speed. The total braking load is distributed over the speed change gear, the flow brake, the torque converter and the engine. In addition, an engine brake and vehicle mechanical friction brakes may be employed.

Abstract: The lock-up control system functions to temporally release lock-up operation of a torque converter of the transmission upon occurrence of a gear shift signal even if the automotive vehicle is operating within lock-up range. A plurality of gear shifting detectors are provided, each generating a gear shift signal when triggered. Gate means function to select one of said plurality of gear shifting detectors in response to engine load for allowing transmission of a gear shifting command to a selected gear shifting detector. Delay means are provided to retard transmission of the gear shifting command to the plurality of gear shifting detectors in such a manner that a delay between the occurrence of the gear shifting command and the occurrence of the gear shift signal increases as the engine load decreases.