| 摘要 |
PURPOSE: An automatic transmission hydraulic control system is provided to prevent a shift quality and a clutch from shortening in life span by momentary occurrence of rear clutch pressure on shifting a gear from 4th to 3rd level. CONSTITUTION: During shifting a gear from 4th to 3rd level, hydraulic pressure is not fed to a third port(27) of a rear clutch discharge valve(13) under control of a first pressure control valve(9). The hydraulic pressure is discharged to the first pressure control valve(9) and the rear clutch discharge valve(13) by complete opening of the valve(9). The hydraulic pressure discharged to a rear clutch(F/C) is absorbed sufficiently by an accumulator(41) to prevent a clutch drag torque of the rear clutch(R/C). The hydraulic pressure in 2-3/4-3 shift valve(17) is supplied to a front clutch(F/C) and a servo release(S/R) to operate the front clutch(F/C) and to release a second brake(2ND/B).
|
