Abstract: An automatic transmission with overdrive, including: a torque converter; a torque converter housing; an oil pump; an overdrive gear mechanism; an overdrive case; an underdrive gear mechanism; a transmission case; and an oil pan. In this automatic transmission, the overdrive gear mechanism is positioned between the torque converter and the underdrive gear mechanism. An exhaust passage is positioned in a lower portion of the overdrive case in side-by-side relationship to an intake passage adapted to introduce oil from the oil pan to the oil pump. As a result, oil is circulated from the oil pump to the hydraulic control device, then to the underdrive gear mechanism and the overdrive gear mechanism and then to the oil pan back to the oil pump.

Abstract: A throttling control valve having a spool-like valve element which is gradually shifted in accordance with increase of a control fluid pressure so as to provide four different passage connections therethrough so as to be able to provide four different flow resistances, and a system for controlling downshift timing of an automatic transmission for vehicles which employs this throttling control valve so as to change delay time in supplying fluid pressure to a lower speed friction engaging means in accordance with governor pressure.

Abstract: A breathing system for an automatic transmission including a fluid torque converter, an oil pump, an overdrive means and an auxiliary gear means each having its own housing and being air-tightly connected with each other in series in said order, the system including a passage extending through the housings of the oil pump, the overdrive means and the auxiliary gear means for releasing the internal space confined in the assembly of the housings to the atmosphere, the passage including a loop portion at a middle portion thereof including two parallel passages, one being located at a lower gravity potential level than the other.

Abstract: A driving system acting in conjunction with a motor vehicle having a torque convertor coaxially coupled to the output shaft of the engine, and transfer means having a driving gear coaxially coupled to the output shaft of the overdrive means and a driven gear coupled to its driving gear. Overdrive means having a planetary gear mechanism are coaxially coupled to the output shaft of the torque convertor, and include an output shaft coupled to the driving gear of the transfer means. An automatic transmission is coaxially coupled to the driven gear of the transfer means and includes a planetary mechanism and friction engaging means to provide the desired mode of operation. A differential gear having a driving gear coupled to the output shaft of the automatic transmission drives the motor vehicle. The automatic transmission is positioned below the overdrive means.