| Required Tools | |||
| Tool | Part Number | Description | Qty |
| A | 1U-5482 | Pressure Adapter Group | 1 |
| NOTICE |
|---|
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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| Illustration 1 | g00781513 |
(1) All wheel drive gear pump (2) Flushing and cooling control valve | |
The charge pressure system has two separate sequence valves. The sequence valves determine the charge pressure and the purge pressure for the all wheel drive system. Both the purge pressure sequence valve and the charge pressure sequence valve need to be adjusted in order to obtain the correct system pressure. The all wheel drive system has a gear pump (1) that is located on left side of the engine. All wheel drive gear pump (1) supplies the pressurized oil to the sequence valves.
Adjusting The Charge Pressure Sequence Valve
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| Illustration 2 | g01241972 |
(2) Flushing and cooling control valve (3) Charge pressure test port (5) Charge pressure sequence valve (6) Purge pressure sequence valve | |
Charge pressure sequence valve (5) and purge pressure sequence valve (6) are located on flushing and cooling control valve (2) .
- Operate the machine in order to bring the hydraulic oil to 46 to 52°C (115 to 125°F).
- Shut off the engine. Install Tooling (A) on charge pressure test port (3) . Charge pressure port (3) is located below the centershift lock cylinder.
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| Illustration 3 | g01058595 |
(3) Charge pressure test port (4) Centershift lock cylinder | |
- Start the engine and turn all wheel drive control (7) to the MANUAL position or to the AUTOMATIC position. Shift the transmission control to first speed forward and set the engine at High idle.
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| Illustration 4 | g00861053 |
(7) All wheel drive control | |
- The pressure at test port (3) should read 3000 ± 70 kPa (435 ± 10 psi).
- If the pressure reading is out of tolerance, stop the machine and adjust charge pressure sequence valve (5) . The charge pressure sequence valve has a set screw and a locknut. One turn of the set screw will change the pressure approximately 3200 kPa (465 psi).
- Repeat Step 3, Step 4 and Step 5 until the pressure is at 3000 ± 70 kPa (435 ± 10 psi).
Adjusting The Purge Pressure Sequence Valve
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| Illustration 5 | g01058620 |
(8) Test port for purge pressure
- The purge pressure should be set when the oil is above 46 to 52°C (115 to 125°F). Set the engine at low idle and set all wheel drive control (7) in the OFF position.
- Install Tooling (A) on test port (8) for purge pressure. The pressure should read 2000 ± 70 kPa (290 ± 10 psi).
- If the pressure reading is out of tolerance, stop the machine and adjust purge pressure sequence valve (6) . The purge pressure sequence valve has a set screw and a locknut. One turn of the set screw will change the pressure approximately 3200 kPa (465 psi).
- Repeat Step 1, Step 2 and Step 3 until the pressure is at 2000 ± 70 kPa (290 ± 10 psi).
- Shut off the engine and remove the pressure gauge.