| 摘要 |
A shift control system for an automatic transmission comprises a shift valve for an auxiliary gear train, an orifice bypass passage and an accumulator for low gear train. The shift valve includes a spool which is movable between a first position where the hydraulic fluid is supplied to a first passage and hydraulic fluid is discharged from a second passage, and a second position where the hydraulic fluid is supplied to the second passage and hydraulic fluid is discharged from the first passage. The orifice bypass valve includes a spool and a pilot port. The former is movable between an interrupting position where the first passage is interrupted from a third passage, and a connecting position where the first passage is connected to the third passage, and it is pressed to the interrupting position by a spring. The latter is connected with a fourth passage or engine brake passage.
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