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

Installation Procedure

Note: Cleanliness is an important factor. Before the installation procedure, all parts should be thoroughly cleaned in cleaning fluid. Allow the parts to air dry. Wiping cloths or rags should not be used to dry parts. Lint may be deposited on the parts which may cause later trouble.

1. Check all of the O-ring seals and the components for wear or damage. Replace the components, if necessary.

2. Lubricate all of the O-ring seals lightly with the lubricant that is being sealed.
   Show/hide table

   Illustration 1	g00569076

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

4. Use Tool (C) and the hoist in order to position differential carrier assembly (23) and bevel gear and differential (31) for installation as a unit onto 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).

5. Use 24 nuts (32) and the hard washers in order to install differential carrier assembly (23), bevel gear and differential (31) and the O-ring seal to planetary transmission and transfer gear (2). Tighten 24 nuts (32) to a torque of 430 ± 60 N·m (317 ± 44 lb ft).

6. Remove Tool (C) from differential carrier assembly (23).
   Show/hide table

   Illustration 2	g00569043

   Show/hide table

   Illustration 3	g00569073

7. Install Tool (B) to planetary transmission and transfer gear (2). Attach Tool (B) to a hoist.

8. Use Tool (B) and the hoist in order to position planetary transmission and transfer gear (2) and differential carrier assembly (23) for installation as a unit onto 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).

9. Use 26 nuts (29), the hard washers, and 25 spacers (30) in order to install planetary transmission and transfer gear (2), differential carrier assembly (23), and the O-ring seal to the rear axle housing assembly. Tighten 26 nuts (29) to a torque of 430 ± 60 N·m (317 ± 44 lb ft).

10. Remove Tool (B) from planetary transmission and transfer gear (2).

11. The following procedure is used to determine the required thickness of shims for the pin:
    Show/hide table

    Illustration 4	g00569036

    Show/hide table

    Illustration 5	g00568992

    1. Install pin (28) and the O-ring into the rear axle housing assembly.

    2. Use Tool (D) (not shown) to measure the distance from the rear axle housing assembly to the end of pin (28). Record this measurement.

    3. Subtract 0.05 ± 0.02 mm (0.0020 ± 0.0008 inch) from the measurement that was recorded in Step 11.b.

    4. Use a micrometer in order to assemble shims (27).

    5. Use two bolts (26) and the hard washers in order to install shims (27) and cover (25) to the rear axle housing assembly.
    Show/hide table

    Illustration 6	g00568984

    Show/hide table

    Illustration 7	g00568981

12. Connect hose assembly (24) to differential carrier assembly (23).

13. Connect hose assembly (22) to differential carrier assembly (23).
    Show/hide table

    Illustration 8	g00568835

14. Connect hose assembly (21).

15. Connect hose assembly (20).
    Show/hide table

    Illustration 9	g00568833

16. Connect hose assembly (19) to the magnetic screen housing.
    Show/hide table

    Illustration 10	g00568770

17. Use Tool (A) (not shown) in order to connect wire harness (17) to the transmission speed sensor at the electrical connection.

18. Install lockwire (18) into the electrical connection of wire harness (17).

    Note: Install the lockwire in the next endbell hole in the clockwise direction.

19. Install bolt (16), the washer and the clip to the transfer case assembly. Tighten bolt (16) to a torque of 135 ± 20 N·m (100 ± 15 lb ft).
    Show/hide table

    Illustration 11	g00568769

20. Use two bolts (15), the washers, and the two grommets in order to install guard (14) to the speed sensor housing.
    Show/hide table

    Illustration 12	g00567637

    Show/hide table

    Illustration 13	g00567635

21. Use bolt (13) in order to install clip (9).

22. Connect wire harness (11) at the three electrical connections, as shown.
    Show/hide table

    Illustration 14	g00567593

23. Use Tool (A) (not shown) in order to connect wire harness (11) to the transmission position sensor at the electrical connection.

24. Install lockwire (10) into the electrical connection of wire harness (11).

    Note: Install the lockwire in the next endbell hole in the clockwise direction.

25. Connect hose assembly (12) and two clips (9), as shown.

26. Connect hose assembly (8).
    Show/hide table

    Illustration 15	g00567592

27. Connect two hose assemblies (7) and (6).
    Show/hide table

    Illustration 16	g00567587

    Show/hide table

    Illustration 17	g00567583

28. Attach a suitable lifting sling around drive shaft (5). Attach the lifting sling to a hoist.

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

29. Use the hoist and the lifting sling in order to position drive shaft (5) for installation.

30. Use a suitable pry bar in order to extend drive shaft (5). Use four new bolts (4) in order to connect drive shaft (5) to the yoke of planetary transmission and transfer gear (2). Tighten four bolts (4) to a torque of 550 ± 20 N·m (405.7 ± 14.8 lb ft).

31. Remove the lifting sling from drive shaft (5).
    Show/hide table

    Illustration 18	g00567576

32. Position guard assembly (1) onto the frame assembly. Use five bolts (3) and the hard washers in order to install guard assembly (1) to the frame assembly.

33. Fill the differential and final drive with hydraulic oil to the correct level. Refer to Operation and Maintenance Manual, SEBU7173, "Differential and Final Drive Oil - Change" for the correct procedure.

34. Fill the transmission system with hydraulic oil to the correct level. Refer to Operation and Maintenance Manual, SEBU7173, " Transmission Tank Oil - Change" for the correct procedure.

End By:

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

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

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