| 摘要 |
Disclosed is a hydraulic control system for an automatic transmission that controls a powertrain, which includes a first friction element for use as an engine brake for discontinuing operation of a one-way clutch in the transmission and a second friction element operating only when the first friction element is disengaged. The hydraulic control system comprises a manual valve including a forward range port for exhausting hydraulic pressure when driving in a forward range, and an L range port for exhausting hydraulic pressure for low speed control; and a switch valve controlled by engine brake signal pressure, solenoid pressure, and forward range pressure supplied from the forward range port, the switch valve selectively supplying control pressure to the first friction element and the second friction element.
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