• Spring force and modifier pressure (21) constantly push the valve to the right side, thus transmitting line pressure (13) to 3-4 clutch pressure (18). Then 3-4 clutch pressure (18) works on the right end of the valve, and moves the valve to the left side.
• As 3-4 clutch pressure (18) increases, the valve moves to the left, in spite of spring force and modifier pressure (21) pushing the valve to the right. Therefore, during 2GR→3GR shifting, line pressure (13) is transmitted to the 3-4 clutch application pressure through the bypass valve, then quickening 3-4 clutch engagement (left side figure).
• Beyond a certain level, the valve closes the path for line pressure (13); the line pressure goes through the orifice check valve, causing a slow increase in 3-4 clutch application pressure (right side figure).
• The modifier pressure (21) applied to the left end of the valve assures that 3-4 clutch application timing matches throttle valve opening angle.
• This process controls 3-4 clutch application timing and shifting shock.
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1
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To 3-2 timing valve
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2
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To 3-4 clutch
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3
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3-4 clutch pressure
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4
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Modifier pressure
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5
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From 2-2 shift valve
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6
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Orifice check valve
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