Case IH AFX8010 Repair Manual page 1571

TRAVELLING - 2WD-4WD SYSTEM Hydraulic
2
50016593A5
Cross Section of Control Valve - "Off" Position
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The return spring (3), Figure 2, and charge pressure directed from the low pressure spool, through port (C) of the
solenoid valve, and through the drilled passage (14), Figure 2, will move and keep the spool (2), Figure 2, to
the left side of the spool bore. This is the "disengaged" position for the spool and the forward and reverse high
pressure ports are closed off.
The rear wheels of the combine will now "freewheel". As the wheels rotate, the wheel motor pistons are pushed
back into their bores. The hydraulic fluid behind the pistons is directed back to the wheel motor supply/return ports
(12, 13), Figure 2, of the valve. From there, the fluid from the right wheel motor flows through the flow dividers (7)
and the right check valve (8) and center passage (9). Hydraulic fluid then flows to the left side wheel motor reverse
supply/return port (12) and to the selector spool (2). Hydraulic fluid that exits the valve at the reverse supply/return
port (12) and from the left wheel motor is directed to the drain valve by a "tee" connection at the reverse supply/return
port (12) Hydraulic fluid flows from the "tee" to the drain valve through an external tube. A drilled passage (15) in the
selector spool allows hydraulic fluid that does not flow out of the valve through the reverse supply/return port (12) to
flow through the spool (2) through the case drain orifice (4) and out of the valve at the pressure to engage port (5).
From there, fluid is directed back to the solenoid valve via an external tube where the fluid drains back to tank.
When the Powered Rear Axle is off, charge pressure that is directed from the solenoid valve to the selector spool is
also directed to the drain valve out of the pressure to disengage port (11), through an external tube. This pressure
shifts the spool in the drain valve that allows hydraulic fluid from the wheel motors (from the "tee" at the reverse
supply/return port (12)) to flow through the drain valve and out. From the drain valve, hydraulic fluid is directed back
to tank through an external tube that connects to the valve drain.
VALVE OPERATION "INTERMEDIATE" POSITION
(Reference Figures 3, 4, and 5)
NOTE: Reference to directions are as if viewing the valve from the rear, facing the front of the combine.
9688 1 27/05/2004
D.14.C / 11