Hydraulic Tank
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| Illustration 1 | g01191262 |
Rear of Operator Platform (1) Hydraulic tank (2) Sight gauge (3) Breather (4) Fill port (5) Return filter (6) Filter indicator (7) Hydraulic oil temperature sensor | |
Hydraulic tank (1) is located to the rear of the operator platform.
The following systems share common hydraulic tank (1) :
- Propel hydraulic systems
- Fan hydraulic system
- Auxiliary hydraulic system
- Water spray system
- Emulsion spray system
Sight gauge (2) indicates the oil level in the tank. The capacity of the hydraulic tank is 233 L (61.5 US gal). The tank is equipped with a breather (3). The breather limits the maximum pressure in the tank to 50 ± 20 kPa (7.3 ± 3 psi). The breather also limits the vacuum which can be created in the tank to a maximum of 2 ± 0.7 kPa (0.3 ± 0.1 psi). Fill port (4) is located to the rear of the breather.
Case drain oil from the following components flow through return filter (5) :
- Front propel pump
- Front propel motor
- Rear propel pump
- Rear propel motor
- Water spray pump
- Water spray motor.
Return oil from the auxiliary system is also sent through the return filter. The filter housing contains filter indicator (6) and a bypass valve. The filter indicator shows whether the filter is plugged or the filter needs to be serviced.
The filter is plugged when the following conditions are met:
- The filter indicator is in the red zone.
- The engine is operating at high idle.
- The oil is at normal operating temperature.
If the pressure differential across the filter is greater than 172 kPa (25 psi), the bypass valve opens. In this case return oil flows directly into the hydraulic tank.
Hydraulic oil temperature sensor (7) is a resistance type sensor. The sensor is installed in the front face of the hydraulic tank (1). The display control panel monitors the resistance through by the sensor. The display converts the resistance into a temperature value.
Cooling Package
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| Illustration 2 | g01191274 |
Front of Machine (8) Cooling package | |
The hydraulic oil cooler is part of cooling package (8). The cooling package is located at the front of the machine.
Case drain oil from the front propel motors and return oil from the fan hydraulic motor is sent through the oil cooler.
Pressure Taps
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| Illustration 3 | g01191286 |
Right Side of Machine | |
Pressure taps for the propel hydraulic system are located behind the platform access ladder, on the right front of the machine.
The following list describes the function of each pressure tap and the pressure specification for the system:
- Front pump, forward pressure tap (12) (40710 ± 690 kPa (5900 ± 100 psi))
- Front pump, reverse pressure tap (13) (40710 ± 690 kPa (5900 ± 100 psi))
- Front pump, charge pressure tap (14) (2830 ± 210 kPa (410 ± 30 psi))
- Rear pump, forward pressure tap (9) (40710 ± 690 kPa (5900 ± 100 psi))
- Rear pump, reverse pressure tap (10) (40710 ± 690 kPa (5900 ± 100 psi))
- Rear pump, charge pressure tap (11) (2410 ± 206 kPa (350 ± 30 psi))
Charge Filters
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| Illustration 4 | g01191298 |
Right Side of Machine (15) Front charge filters (16) Rear charge filters (17) Pressure switch (18) Pressure switch | |
Front charge filter (15) and rear charge filter (16) are located behind the platform access ladder, on the right front of the machine.
Note: Only machines which are equipped with the optional all wheel drive system have a rear propel pump and corresponding rear pump charge filter (16) .
The base of each charge filter contains a bypass valve and pressure switch (17) and (18). When the pressure differential across either filter is greater than 250 kPa (36 psi), the bypass valve in the filter base opens. In this case, oil flows around the charge filter.
Front Flow Divider
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| Illustration 5 | g01191454 |
Below PTO Output Yoke (19) Front flow divider (20) Front flow divider solenoid | |
Front flow divider solenoid (20) is mounted to front flow divider valve (19). This valve is located next to the left frame rail, under the machine.
Front flow divider valve (19) ensures that equal oil flow is sent to each front propel motor. Equal flow through the propel motors results in equal wheel speed, regardless of underfoot conditions. The machine ECM will discontinue the signal to flow divider solenoid (20) if propel speed reaches approximately 32 m/min (105 ft/min). This is done in order to reduce heat generation in the system at high flow rates. The machine ECM will also discontinue the signal to the flow divider solenoid if the steering radius becomes too tight. This is done in order to prevent one front wheel from over driving the other front wheel during tight turns.
Note: The control for the traction control feature is open loop for commanded speed and the control is closed loop for the front steering angle.
The ports on the freewheel valve are marked for identification purposes.
The following describes each port:
- "P1" (This port is connected to port "B" on the front propel pump and port "B" on the rear propel pump.)
- "CHG" (This port is connected to the charge filter for the front propel pump.)
- "A" (This port is connected to port "A" on the left front propel motor.)
- "B" (This port is connected to port "B" on the right front propel motor.)
- "T" (This port is connected to the hydraulic tank.)
Freewheel Valve
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| Illustration 6 | g01191473 |
Above Rear Steering Cylinder (21) Freewheel valve (22) Rear flow divider solenoid (23) Rear freewheel solenoid | |
Machines which have the optional rear wheel drive system are equipped with freewheel valve (21) .
Freewheel valve (21) houses control solenoids and an integral rear flow divider. The freewheel valve turns the rear wheel drive system on and off. Also, the rear flow divider hydraulically couples the rear wheels together for increased traction. Rear flow divider solenoid (22) and rear freewheel solenoid (23) are mounted on the bottom of the freewheel valve. This valve is located on the left rear frame rail immediately above the rear steering cylinder.
Rear flow divider solenoid (22) is energized by the fan control module. This solenoid is energized in parallel with the front flow divider. Consequently, the function of the rear flow divider solenoid is the same as the front flow divider solenoid. The rear flow divider is a slave to the front flow divider.
Rear freewheel solenoid (23) engages the rear wheels when the rear wheel assist toggle switch is ON. When the rear freewheel solenoid is de-energized, the rear propel motors spin freely. When the rear freewheel solenoid is energized, the rear propel motors transfer fluid power to the rear wheels. The rear freewheel solenoid is energized by the fan controller. The target speed of the rear wheels is proportional to the target speed of the front wheels.
The ports on the freewheel valve are marked for identification purposes.
The following describes each port:
- "PAR" (This port is connected to port "A" (forward) of the rear propel pump.)
- "PAV" (This port is connected to port "B" (reverse) of the rear propel pump.)
- "G" (This port receives charge oil from the front propel charge circuit.)
- "CD1" (This port delivers charge oil from port "G" to the side case drain port of the rear propel motors.)
- "CD2" (This port receives case drain oil from the top case drain ports on both motors.)
- "ARL" (This port is connected to port "A" of the left rear propel motor.)
- "ARR" (This port is connected to port "B" of the right rear propel motor.)
- "AVL" (This port is connected to port "B" of the left rear propel motor.)
- "AVR" (This port is connected to port "A" of the right rear propel motor.)
- "D" (This port is the drain port connected to the hydraulic tank.)
Auxiliary Pump
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| Illustration 7 | g01191548 |
Rear of Engine Compartment (24) Auxiliary pump | |
Auxiliary pump (24) is an axial piston pump. This pump is variable displacement and is pressure compensated. The auxiliary pump is mounted behind the front propel pump, under the operator platform. The auxiliary pump provides the oil which releases the front brakes. The auxiliary pump also provides the oil which shifts the front piston motors into "HIGH" speed.