Abstract: A transmission case is provided with a housing enclosing a clutch and/or torque converter connected to an engine, and a shifting mechanism case enclosing a shifting mechanism in an oil-tight state that is connected to the housing. A focus for stress resulting from an impact load acting on the transmission case is formed as a frangible portion in the housing. Thus, damage to the transmission from an excessive load is limited to the housing, and by absorbing the impact from that damage, damage to the shifting mechanism case is prevented and oil leakage from the transmission case is avoided.

Abstract: In a breather device linking a space within a transmission case (1) to outside air, a breather (10) is provided at a middle position in a lengthwise direction on an upper portion of the transmission case, in particular, at a position displaced in an axial direction from a middle position in the lengthwise direction, and opens to outside air via a ventilating mechanism (2) that extends in a direction opposite this displaced direction.

Abstract: A transmission has an oil drain passage for connecting an oil reservoir with a mission case in a pump casing. The automatic transmission has also a retainer serving as a shielding member to shield between a discharge opening of the oil drain passage from at least part of a multistage transmission mechanism. This ensures that breather oil blow, which is caused by the spattering and stirring of operating oil by the high-speed drum member, is shielded from at least part of the transmission mechanism.

Abstract: A transmission has an oil drain passage for connecting an oil reservoir with a mission case in a pump casing. The automatic transmission has also a retainer serving as a shielding member to shield between a discharge opening of the oil drain passage from at least part of a multistage transmission mechanism. This ensures that breather oil blow, which is caused by the spattering and stirring of operating oil by the high-speed drum member, is shielded from at least part of the transmission mechanism.

Abstract: A transmission case is provided with a housing enclosing a clutch and/or torque converter connected to an engine, and a shifting mechanism case enclosing a shifting mechanism in an oil-tight state that is connected to the housing. A focus for stress resulting from an impact load acting on the transmission case is formed as a frangible portion in the housing. Thus, damage to the transmission from an excessive load is limited to the housing, and by absorbing the impact from that damage, damage to the shifting mechanism case is prevented and oil leakage from the transmission case is avoided.

Abstract: In a breather device linking a space within a transmission case (1) to outside air, a breather (10) is provided at a middle position in a lengthwise direction on an upper portion of the transmission case, in particular, at a position displaced in an axial direction from a middle position in the lengthwise direction, and opens to outside air via a ventilating mechanism (2) that extends in a direction opposite this displaced direction.