769D Off-Highway Truck and 771D Quarry Truck Caterpillar

The machine must be level. The parking brake must be engaged and the engine must be stopped.

1. Remove the filler cap in order to prevent a vacuum in the tank. Install the cap after the tank has been drained. This will prevent dirt from entering the system.

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Illustration 1	g00524218

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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 Tools and Shop Products Guide" for tools and supplies suitable to collect and contain fluids on Caterpillar products. Dispose of all fluids according to local regulations and mandates.

Note: Hand tighten the NPT pipe nipple. Do not use tools.

2. Remove the tank drain plug. Install a 88 mm (3.50 inch) long NPT pipe nipple in order to open the internal drain valve. The outer diameter of the NPT pipe nipple should be 25.4 mm (1 inch). Drain the oil into a suitable container.

3. Remove the front cover from the tank.

4. Clean the debris from the bottom of the tank.

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Illustration 2	g00525805

5. Remove the return line.

6. Remove the return screen and discard the screen.

7. Install a new screen, a new cover, the return line and new retaining bolts.

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Illustration 3	g00524210

8. Remove the suction line.

9. Remove the suction screen from the tank.

10. Wash the suction screen and the retaining bolts in clean, nonflammable solvent.

11. Install the clean suction screen, the suction line and the clean retaining bolts.

12. Clean the cover for the front of the hoist and brake tank in clean, nonflammable solvent. Inspect the cover gasket. If the gasket is damaged, replace the gasket.

13. Install the cover to the front of the tank.

14. Fill the hoist and brake tank. Refer to Operation and Maintenance Manual, "Lubricant Viscosities". Refer to Operation and Maintenance Manual, "Capacities (Refill)".

15. Add oil to the tank in order to raise the oil level to the safe starting range.

16. Start the engine and run the engine for approximately 15 seconds. The oil level will decrease as oil fills the system.

17. Stop the engine.

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Illustration 4	g00791820

18. Check the oil level in the tank. Fill the tank to the "FULL COLD" mark in the upper sight gauge.

19. Raise the dump body until the hoist cylinders are extended halfway. Lower the dump body and add oil, if necessary.

20. Raise the dump body until the hoist cylinders are fully extended. Lower the dump body and add oil, if necessary.

21. Repeat Step 19 and Step 20 until the oil level stabilizes. Maintain the oil level to the "FULL WARM" mark in the upper sight gauge.

22. Stop the engine. Install the filler cap.