Automatic transmission provided with mode preventing increase in oil temperature

Claim 1

An automatic transmission driven by an output shaft of an engine and provided with a torque converter, a plurality of gear-change steps, a plurality of gear-change patterns which select said gear-change steps as are determined by the rotational speed of the output shaft and throttle opening of the engine, an automatic gear means for automatically changing said gear-change steps on the basis of said gear-change patterns, and a transmission oil temperature sensor which generates a transmission oil temperature signal comprising an oil temperature increase prevention mode which automatically shifts gears on the basis of a gear-change pattern of said mode, and which is one of a plurality of gear-change patterns, in which downshift points are shifted to a gear-change based on a speed higher than a standard gear-change pattern when said oil temperature signal is above a level of a signal corresponding to a given temperature; and a control means for determining when oil temperature has increased to a given temperature on the basis of said oil temperature signal, and generating a control signal so as to change said mode to said oil temperature increase preventive mode.