| 摘要 |
PURPOSE:To operate friction elements by means of a manual valve even if a control valve to drain the operating pressure of the friction element corresponding to the friction of a one way clutch is stuck to a draining position. CONSTITUTION:A valve 16, which is positioned at a lowering position with the fourth speed selected, by which a band brake B/B is engaged by fourth speed selection pressure P4, and a valve 18 can be positioned at a lowering position by turning off a solenoid C. With this constitution, the operating pressure of a clutch F/C is drained to prevent the friction of a one way clutch relating to the operating pressure. When the valve 18 is stuck to a lowering position, the operation of the clutch F/C becomes impossible, prohibiting the selection of the first speed through the third speed, but at this time, the second range is selected for a manual valve 14 to send pressure to a circuit 20. By this pressure, the clutch F/C is operated allowing the selection of the first speed through the third speed. |
