Abstract: An automatic transmission is provided with a gear train comprising a plurality of rotation elements for selecting one of a preset plurality of gear ratios between an input shaft and an output shaft. Further provided is a one way clutch which prevents rotation of a specific rotation element in one direction. By decreasing the acceleration of this rotation element in the reverse direction when there is a gear change such that the rotation direction of the element changes to reverse, acceleration of the element in the reverse direction is suppressed to a small value when the one way clutch prevents reverse rotation of the element, and impact due to stopping reverse rotation is thereby damped.

Abstract: A lockup control system for automatic transmissions is constructed to determine a rate of change of the drive duty of a lockup solenoid so that the drive duty has a value for obtaining the converter state of a torque converter within a set time determined for every type of shift.

Abstract: Herein disclosed is a wire harness arrangement of an automatic transmission control valve unit. Covered wires extend from a front surface of a body of the control valve unit to a rear surface of the same through a side surface of the same. A plurality of brackets are arranged on the front surface in a manner to define therebetween at least one guide channel in and along which the wires extend. Closure arms are bolted to one of the brackets to partially cover the guide channel thereby to prevent the wires from being disengaged from the guide channel. A cover member is bolted to the side surface of the control valve unit in a manner to retain the wires at the side surface.