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| Illustration 1 | g00488201 |
Hydraulic System Schematic (1) Priority valve. (2) Lockup clutch solenoid valve (if equipped). (3) Impeller clutch solenoid valve. (4) Transmission hydraulic controls. (5) Oil filter. (6) Oil filter. (7) Torque converter. (8) Lockup clutch (if equipped). (9) Impeller clutch. (10) Oil pump. (11) Torque converter outlet relief valve. (12) Flow control orifice. (13) Magnetic screen. (14) Oil cooler. (15) Reservoir in output transfer gear case. (16) Outlet line from oil cooler to planetary lubrication. (A) Oil pump output pressure tap P1. (B) Pressure tap for oil pump. (C) Pressure tap for lockup clutch (if equipped). (D) Torque converter inlet pressure tap P3. (E) Pressure tap for oil pump. (F) Pressure tap for impeller clutch. (G) Lubrication pressure tap. (H) Torque converter outlet pressure tap. | |
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| Illustration 2 | g00107979 |
992G Wheel Loader Torque Converter Cover (C) Pressure tap for lockup clutch (if equipped). (F) Pressure tap for impeller clutch. | |
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| Illustration 3 | g00411458 |
Transmission (D) Torque converter inlet pressure tap P3. | |
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| Illustration 4 | g00107981 |
992G Wheel Loader Torque Converter Cover (H) Torque converter outlet pressure tap. | |
| NOTICE |
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Care must be taken to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting and repair of the product. Be prepared to collect the fluid with suitable containers before opening any compartment or disassembling any component containing fluids. Refer to Special Publication, NENG2500, "Caterpillar Dealer Service Tool Catalog" for tools and supplies suitable to collect and contain fluids on Caterpillar products. Dispose of all fluids according to local regulations and mandates. |
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Personal injury or death can result from sudden machine movement. Sudden movement of the machine can cause injury to persons on or near the machine. Prevent possible injury by performing the procedure that follows before working on the machine. |
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- Park the machine on a smooth level surface.
- Shift the STIC transmission direction control switch to the NEUTRAL position.
- Lower the bucket and/or the attachment to the ground. Lower the blade and/or the attachment to the ground.
- Engage the parking brake.
- Place blocks in front of the wheels and behind the wheels.
- Install the steering frame lock.
- Allow only authorized personnel on the machine. Keep unauthorized personnel off the machine and in clear sight of the operator.
Note: All tests and all adjustments must be made while the transmission oil is at normal operating temperature.
| NOTICE |
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Do not connect or disconnect hose fittings to or from the quick disconnect nipples when there is pressure in the system. This will prevent damage to the seals that are in the fitting. |
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| Illustration 5 | g00107976 |
Outlet Relief Valve (11) Torque converter outlet relief valve. (17) Spacers. | |
| Torque Converter Pressure | |||
| Pressure | Pressure Tap | Pressure at High Idle | Adjustment |
| Lockup Clutch (If equipped) | (C) | Stabilized pressure with an activated solenoid is 2000 kPa (290 psi) to 2137 kPa (310 psi). Pressure is less than 170 kPa (25 psi) when the solenoid is not activated. |
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| Torque Converter Inlet | (D) | Maximum pressure with cold oil is 930 kPa (135 psi). |
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| Impeller Clutch | (F) | Maximum pressure is 2585 ± 205 kPa (375 ± 30 psi). Pressure two seconds after a shift is 2275 ± 205 kPa (330 ± 30 psi). (1) Minimum pressure is 415 ± 205 kPa (60 ± 30 psi). (1) |
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| Maximum pressure is 2482 ± 207 kPa (360 ± 30 psi). (2) Minimum pressure is 415 ± 205 kPa (60 ± 30 psi). (2) |
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| Torque Converter Outlet | (H) | Maximum pressure is 550 kPa (80 psi). Minimum pressure is 415 kPa (60 psi). (These pressures are for a machine in third speed, with activated brakes, with installed axle shafts, and with the converter in a stall condition.) |
Add spacers (17) or remove spacers (17) . |
| ( 1 ) | (S/N: 7HR1-UP) |
| ( 2 ) | (S/N: ADZ1-UP, AZX1-UP) |
| Pressure Change for One Spacer (1) | |||
| Description | Thickness | Pressure Change | Part |
| 5M-9623 Spacer | 0.91 mm (.036 inch) |
18.2 kPa (2.64 psi) |
Output Relief Valve (11) |
| 5M-9624 Spacer | 0.25 mm (.010 inch) |
5.0 kPa (.73 psi) |
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| ( 1 ) | Before an adjustment is made to outlet relief valve (11) , make sure that the valve springs are not weak or broken. |
| Required Tools | ||
| Part Number | Description | Quantity |
| 1U-5481 | Pressure Gauge Group | 1 |
| 1U-5482 | Pressure Adapter Group | 1 |
Lockup Clutch Disengaged (Minimum clutch pressure)
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The drive shaft rotates between the torque converter and the transmission whenever the engine is running. Contact with the rotating shaft can result in personal injury or death. The rotating shaft is located under the implement and steering pumps. Do not allow personnel into the pump bay area behind the cab when the engine is running. |
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Personal injury or death can result from sudden machine movement. Sudden movement of the machine can cause injury to persons on or near the machine. To prevent injury or death, make sure that the area around the machine is clear of personnel and obstructions before moving the machine to perform the test that follows. |
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- Install a hose and a 4130 kPa (600 psi) pressure gauge on pressure tap (C) .
- Engage the parking brake and shift the transmission to neutral. Start the engine and run the engine at high idle.
- Observe the pressure gauge. The pressure reading on the gauge must be 170 kPa (25 psi) or less.
Lockup Clutch Engaged (Maximum stabilized pressure)
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The drive shaft rotates between the torque converter and the transmission whenever the engine is running. Contact with the rotating shaft can result in personal injury or death. The rotating shaft is located under the implement and steering pumps. Do not allow personnel into the pump bay area behind the cab when the engine is running. |
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Personal injury or death can result from sudden machine movement. Sudden movement of the machine can cause injury to persons on or near the machine. To prevent injury or death, make sure that the area around the machine is clear of personnel and obstructions before moving the machine to perform the test that follows. |
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- Install a hose and a 4130 kPa (600 psi) pressure gauge on pressure tap (C) .
- Remove the steering frame lock.
- Remove blocks from the wheels.
- Move the on/off switch for the torque converter lockup clutch (if equipped) to the ON position.
- Engage the parking brake and place the transmission in neutral. Start the engine.
- Apply the service brakes and release the parking brake. Place the 992G Wheel Loader in first speed forward. Place the 854G Wheel Tractor in second speed forward.
- Operate the machine at maximum speed and observe the pressure reading on the gauge. Make sure that the left service brake pedal or the right service brake pedal are not depressed. If the left service brake pedal or the right service brake pedal are depressed the lockup clutch will not engage. The maximum stabilized pressure must be 2000 kPa (290 psi) to 2137 kPa (310 psi).