HYDRAULIC SYSTEM RT880E SERVICE MANUAL
2-68 Published 11-10-2014, Control # 524-00
RANGE SHIFT/PARKING BRAKE VALVE
Description
The range shift/parking brake valve Figure 2-36 controls the
flow of oil to the parking brake, hi-low range and axle
disconnect actuators by the use of two solenoid valves. The
valve is located on the center of the frame. Pressure is
supplied to the valve from the transmission charge pump.
The parking brake solenoid valve is a two position three-way
valve. In its de-energized position, the inlet port is blocked
and the parking brake actuator is drained to the reservoir.
When the solenoid is energized, the reservoir port is blocked
and pressurized oil is directed to the actuator, engaging the
parking brake.
The range shift solenoid valve is a two position four-way
valve. In its de-energized position, pressurized oil flows to
the “A” port of the range shift actuator, while the “B” port is
drained to the reservoir along with the axle disconnect
actuator for two wheel drive/high range. When the solenoid
is energized, pressurized oil is directed to the “B” port of the
range shift actuator and the axle disconnect actuator while
port “A” of the range shift actuator is drained to the reservoir
for four wheel drive/low range.
Maintenance
Removal
1. Tag and disconnect the electrical connectors to the
valve.
2. Tag and disconnect the hydraulic hoses from the valve.
Cap or plug the lines and ports.
3. Remove the capscrews, lockwashers and nuts securing
the valve to the frame. Remove the valve.
Installation
1. Secure the valve to the frame with the nuts, flatwashers,
lockwashers and capscrews. Torque capscrews; refer to
Fasteners and Torque Values, page 1-15 for the proper
torque value.
2. Connect the hydraulic hoses to the ports on the valve as
tagged during removal.
3. Connect the electrical connectors to the valve as tagged
during removal.
Functional Tests
1. Start and idle engine.
2. With units on outriggers, check for proper two/four wheel
operation.
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8
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8
6697-2
6697-1
FIGURE 2-36
Item Description
1 Port P - Pressure
2 Port T - Tank
3 Port A - Range Shift Actuator
4 Port B - Range Shift Actuator
5 Port PB - To Park Brake
6 Solenoid Valve - Range Shift
7 Solenoid Valve - Park Brake
8 Pressure Switch
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