784C and 785C Off-Highway Truck Power Train Caterpillar

Removal Procedure

Start By:

1. Install the wheel chocks. Refer to Disassembly and Assembly, SENR1500, "Wheel Chocks (Front and Rear) - Remove and Install".

2. Install the retaining cable. Refer to Disassembly and Assembly, SENR1500, "Body Retaining Cable - Remove and Install".

3. Remove the axle shafts (left and right). Refer to Disassembly and Assembly, "Axle Shaft - Remove".

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The space between the body and the frame becomes a zero clearance area when the body is lowered. Failure to install the retaining cable can result in injury or death to personnel working in this area.

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At operating temperature, the hydraulic tank is hot and under pressure. Hot oil and components can cause personal injury. Do not allow hot oil or components to contact skin. Remove the filler cap only when the engine is stopped, and the filler cap is cool enough to touch with your bare hand. Remove the filler cap slowly in order to relieve pressure.

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Personal injury can result from hydraulic oil pressure and hot oil. Hydraulic oil pressure can remain in the hydraulic system after the engine has been stopped. Serious injury can be caused if this pressure is not released before any service is done on the hydraulic system. Make sure all of the attachments have been lowered, oil is cool before removing any components or lines. Remove the oil filler cap only when the engine is stopped, and the filler cap is cool enough to touch with your bare hand.

Note: Put identification on all hose assemblies, on all wire harnesses, and on all tube assemblies for installation purposes. Plug all hose assemblies and all tube assemblies. This helps to prevent fluid loss and this helps to keep contaminants from entering the system.

Note: Cleanliness is an important factor. Before the removal procedure, the exterior of the component should be thoroughly cleaned. This will help to prevent dirt from entering the internal mechanism.

1. Drain the hydraulic oil from the transmission system. The transmission system contains approximately 248 L (66 US gal). Refer to Operation and Maintenance Manual, SEBU7173, "Transmission Tank Oil - Change" for the correct procedure.

2. Drain the hydraulic oil from the differential and final drive. The differential and final drive contain approximately 526 L (139 US gal). Refer to Operation and Maintenance Manual, SEBU7173, "Differential and Final Drive Oil - Change" for the correct procedure.
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   Illustration 1	g00568767

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   Illustration 2	g00567576

3. Position a suitable container under planetary transmission and transfer gear (2) in order to contain hydraulic oil for storage or disposal.

4. Remove five bolts (3) and the hard washers in order to remove guard assembly (1) from the frame assembly.
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   Illustration 3	g00567583

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   Illustration 4	g00567587

5. Attach a suitable lifting sling around drive shaft (5). Attach the lifting device to a hoist in order to support drive shaft (5).

   Note: Attach the lifting sling to the center point of drive shaft (5). This will help to balance drive shaft (5).

6. Remove four bolts (4) and the hard washers in order to separate drive shaft (5) from the yoke of planetary transmission and transfer gear (2). Use a suitable pry bar in order to compress drive shaft (5).
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   Illustration 5	g00567592

7. Disconnect hose assembly (6).

8. Disconnect hose assembly (7).
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   Illustration 6	g00567593

9. Disconnect hose assembly (8).

10. Disconnect hose assembly (12). Remove two clips (9).

11. Remove lockwire (10) from the electrical connection of wire harness (11).

12. Use Tool (A) (not shown) in order to disconnect wire harness (11) from the transmission position sensor at the electrical connection.
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    Illustration 7	g00567635

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    Illustration 8	g00567637

13. Disconnect wire harness (11) at the three electrical connections.

14. Remove bolt (13) and clip (9). Position wire harness (11) out of the way.
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    Illustration 9	g00568769

15. Remove two bolts (15), the washers, and the two grommets in order to remove guard (14) from the speed sensor housing.
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    Illustration 10	g00568770

16. Remove lockwire (18) from the electrical connection of wire harness (17).

17. Remove bolt (16), the washer, and the clip from the transfer case assembly.

18. Use Tool (A) (not shown) in order to disconnect wire harness (17) from the transmission speed sensor at the electrical connection.
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    Illustration 11	g00568833

19. Disconnect hose assembly (19) from the magnetic screen housing.
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    Illustration 12	g00568835

20. Disconnect hose assembly (20).

21. Disconnect hose assembly (21).
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    Illustration 13	g00568981

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    Illustration 14	g00568984

22. Disconnect hose assembly (22) from differential carrier assembly (23).

23. Disconnect hose assembly (24) from differential carrier assembly (23).
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    Illustration 15	g00568992

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    Illustration 16	g00569036

24. Remove two bolts (26) and the hard washers in order to remove cover (25) and shims (27).

25. Remove pin (28) and the O-ring seal from the rear axle housing assembly.
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    Illustration 17	g00569043

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    Illustration 18	g00569073

26. Install Tool (B) to planetary transmission and transfer gear (2). Attach Tool (B) to a hoist in order to support planetary transmission and transfer gear (2).

27. Remove 26 nuts (29), the hard washers, and 25 spacers (30). Remove planetary transmission and transfer gear (2), differential carrier assembly (23) and the O-ring seal as a unit from the rear axle housing assembly. The weight of planetary transmission and transfer gear (2) and differential carrier assembly (23) as a unit is 3175 kg (7000 lb).
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    Illustration 19	g00569076

28. Position planetary transmission and transfer gear (2) and differential carrier assembly (23) onto a suitable stand.

29. Install Tool (C) to differential carrier assembly (23). Attach Tool (C) to a suitable lifting device. Attach the lifting device to a hoist. Attach a suitable lifting device and the hoist to bevel gear and differential (31), as shown.

30. Remove 24 nuts (32) and the hard washers. Remove differential carrier assembly (23), bevel gear and differential (31), and the O-ring seal from planetary transmission and transfer gear (2). The weight of differential carrier assembly (23) and bevel gear and differential (31) as a unit is 862 kg (1900 lb).