| 摘要 |
PURPOSE: A hydraulic control system for an automatic transmission is provided to reduce shift shock and improve the quality of the automatic transmission by keeping the control pressure constantly in shifting from 3 to 2 or to 4-range. CONSTITUTION: A manual valve supplies and discharges line pressure corresponding to each range, and a shift control unit(15) supplies and discharges pressure with controlling the line pressure. Frictional factors are operated and released by supplying and discharging hydraulic pressure from the selected frictional factor among a front clutch, a rear clutch, an end clutch, a low reverse brake and a kickdown brake. A hydraulic distributing unit(19) controls hydraulic pressure to the front clutch and the servo release of the kickdown brake. Engine rpm is increased in shifting from 3 to 2-range, and decreased in shifting from 3 to 4-range with controlling the hydraulic pressure of the front clutch.
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