Impreza 2.5 RS Sedan AWD F4-2.5L SOHC (2002)
The transfer hydraulic pressure control unit includes a valve body attached to the side of the extension case through a gasket and separator plate.
The pressurized fluids for the transfer hydraulic pressure control (line pressure and pilot pressure) are supplied from the oil pump by way of the
passages formed in the transmission case and then the passages in the extension case that lead to the hydraulic circuit in the transfer valve body.
The line pressure is regulated by the transfer control valve whose opening is controlled by the transfer pressure created by the transfer duty
solenoid.
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The transfer duty solenoid is controlled by the TCM. The TCM changes the solenoid controlling duty ratio according to the driving conditions.
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The transfer duty solenoid creates the transfer pressure from the pilot pressure. The transfer pressure is applied to the transfer control valve and
adjusts the valve's opening.
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The line pressure directly led to the transfer control valve, on the other hand, is regulated by the transfer control valve and becomes the transfer
clutch pressure.
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The transfer clutch pressure is applied to the transfer clutch and engages the clutch to a controlled degree.
In this way, the degree of transfer clutch engagement is varied so that optimum torque is distributed to the rear wheels according to vehicle
driving conditions.
2. TURBO MODEL
The drive power distribution system includes a valve body attached to the side of the extension case through a gasket and separator plate.
The pressurized fluids for the drive power distribution system (line pressure and pilot pressure) are supplied from the oil pump by way of the
passages formed in the transmission case and then the passages in the extension case that lead to the hydraulic circuit in the transfer valve body.
The line pressure is regulated by the transfer control valve whose opening is controlled by the transfer pressure created by the transfer duty
solenoid.
^
The pilot pressure created by passing through the pilot valve in the transmission's hydraulic control assembly is further regulated into the
transfer pressure by the transfer duty solenoid.
^
The transfer duty solenoid is controlled by the TCM. The TCM changes the solenoid controlling duty ratio according to driving conditions.
^
The transfer pressure thus created is applied to the transfer control valve and adjusts the valve's opening.
^
The line pressure directly led to the transfer control valve, on the other hand, is regulated by the transfer control valve and becomes the transfer
clutch pressure.
^
The transfer clutch pressure is applied to the multi-plate clutch (LSD) and engages the clutch to a controlled degree.
In this way, the degree of multi-plate clutch engagement is varied so that optimum torque is distributed to the rear wheels.
