793C Off-Highway Truck/Tractor Power Train Caterpillar

Removal Procedure

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At operating temperature, the oil in the power train is hot and under pressure. Hot oil can cause burns. Remove the breather filter cap when the engine is stopped and the breather cap is cool enough to touch by hand. Slowly loosen the breather filter cap in order to release any pressure in the oil tank. Be careful of hot hydraulic oil when any lines are disconnected from the components of the power train.

Note: The removal procedure and the installation procedure of the axle shafts are identical for both sides of the machine. The following procedure shows the right rear axle. The tires and the rims are removed in the photos. The removal of the tires and the rims is not necessary for the removal of the axle shafts.

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Illustration 1	g00515113

1. Start the machine. Move the machine forward or backward until drain plug (1) is in the position that is shown. Position a suitable container in order to collect the oil from the final drives and the differential. Remove drain plug (1) and gasket (2). Drain the oil from the final drive. Approximately 80 L (21.1 US gal) of oil must be collected.
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   Illustration 2	g00515115

2. Remove two bolts (4) and two washers from cover (3). Install two M12 - 1.75 x 200 guide bolts, as shown.

3. Remove remaining ten bolts (4) and ten washers. Separate cover (3) from the second reduction planetary carrier enough for the installation of Tool (A).
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   Illustration 3	g00515116

4. Use Tool (A) and a suitable hoist to support the weight of cover (3). The cover assembly weighs approximately 64 kg (141.1 lb).

5. Remove cover (3). Place the cover on a suitable bench. If necessary, remove the guide bolts.
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   Illustration 4	g00515117

6. If necessary, remove plug (5) and O-ring seal (6) from the opposite side of the cover.

7. Remove two screws (8) and thrust washer (7).

8. Remove four bolts (9), four washers, and thrust plate (10).
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   Illustration 5	g00515118

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   Illustration 6	g00515119

9. Remove O-ring seal (11).

10. Thread Tool (B) on the rear axle shaft. Use a suitable hoist to support the weight of Tool (B).

    Note: Tool (B) has been installed for the removal of sun gear (12) of the second reduction planetary component and the sun gear of the first reduction planetary component.

11. Use a strap and a suitable hoist to remove gear (12). Gear (12) weighs approximately 74 kg (163.1 lb).
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    Illustration 7	g00515121

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    Illustration 8	g00515123

12. If gear (12) cannot slide out of the second reduction planetary carrier, the parking brake may need to be released. Then, the wheel should be rotated. The following procedure is for the release of the parking brake and the rotation of the rear wheel:

    1. Remove hose (13) and O-ring seal (14). Approximately 4 L (1.1 US gal) of oil must be collected.

       Note: The parking brake port is identified by a "P" that is cast into the brake anchor.

    2. Remove elbow (15) and O-ring seal (16).

    3. Install Tool (C).

       Note: Do not apply more than 4150 kPa (601.9 psi) of oil pressure. If the oil pressure is above 4150 kPa (601.9 psi), the seals and other parts of the circuit could be damaged.

    4. Use Tool (C) to apply approximately 3445 kPa (499.7 psi) of oil pressure.

    5. Maintain the oil pressure of 3445 kPa (499.7 psi). Use a bar to slightly turn the wheel.
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    Illustration 9	g00515124

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    Illustration 10	g00515126

13. Use Tool (D) to remove retaining ring (17).

14. Use a strap and a suitable hoist to remove gear (18). Gear (18) weighs approximately 23.4 kg (51.6 lb).

15. Remove bearing (19).

16. Use Tool (B) to remove rear axle shaft (20).

    Note: During the removal of axle shaft (20), carefully slide the axle shaft through the timing gear in order to avoid the damage to the timing gear.

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    Illustration 11	g00515147

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    Illustration 12	g00515148

17. Remove Tool (B) from the axle. The right rear axle shaft weighs approximately 150 kg (330.7 lb).

    Note: The left rear axle shaft weighs approximately 158 kg (348.3 lb).

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    Illustration 13	g00515149

18. If necessary, remove four bolts (21) and two clamps (22) from the shaft.