| 摘要 |
<p>PURPOSE:To reduce the occurrence of a speed change shock and to promote a temperature rise of operation oil by providing means for prohibiting the selection of a maximum speed change step while the temperature of operation oil of an automatic speed change gear is lower than a fixed value. CONSTITUTION:While the temperature of operation oil of an automatic speed change gear is lower than a preset value, a thermo-switch 66 is closed, and a signal ST is L-level. In response to the signal, NAND gate 70 applies a H-level signal to the base of a transistor Tr. Therefore, the transistor Tr is caused to conduct, and OD releasing solenoid 198 is energized by a power source 67, which results in that the automatic speed change gear is released from overdrive, and the overdrive is not selected even under the overdrive running conditions.</p> |
