621G and 623G Wheel Tractor Power Train Caterpillar

Installation Procedure

1. Clean all parts and inspect all parts. If any parts are worn or damaged, use new Caterpillar parts for replacement.

2. Lubricate O-ring seals with the lubricant that is being sealed.

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Illustration 1	g00817266

3. Install the two O-ring seals to each of eight sleeves (39). Install the six O-ring seals to the bottom of manifold (40). Install eight sleeves (39) to manifold (40) .

4. Install eight sleeves (39) with manifold (40) to the tractor transmission manifold assembly. Install two bolts (38). Tighten the bolts to a torque of 48 ± 4 N·m (35 ± 3 lb ft).

5. Install two O-ring seals to the sleeve. Install the sleeve into elbow (37). Install the sleeve and the elbow to manifold (40). Install two bolts (36). Tighten the bolts to a torque of 30 ± 4 N·m (22 ± 3 lb ft).

6. Install the two O-ring seals to each sleeve (35). Slide the two sleeves (35) through the transmission case and into manifold (40). Install three bolts (34). Tighten the bolts to a torque of 48 ± 4 N·m (35 ± 3 lb ft).

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Illustration 2	g00817262

7. Position plate (33) on the manifold. Install bolt (32) that secures plate (33) to the manifold.

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Illustration 3	g00817259

8. Position selector pressure control valve (31) to the plate. Install twelve bolts (29) and bolt (30) that secure selector pressure control valve to the plate.

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Illustration 4	g00817240
The view is on the left side of the transmission case and under the left fender.

9. Install the O-ring seals to each end of the sleeves. Install two sleeves (28) to the transmission case.

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Illustration 5	g00817245

10. Install the O-ring seals to manifold (25). Position manifold (25) to the transmission case. Install bolt (26) and three nuts (27) that secure manifold (25) to the transmission case.

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Illustration 6	g00817258

11. Install the O-ring seals and connect the two tubes. Install eight bolts (23), the washers, and four half flanges (24) that secure the two tubes to manifold (25) .

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Illustration 7	g00817255

12. Position manifold assembly (14) near the transmission. Install cable assembly (22) through the manifold assembly. Install the retaining ring that secures cable assembly (22) to the back side of manifold assembly (14). Position manifold assembly (14) on the transmission case. Install four bolts (21) that secure manifold assembly (14) to the transmission case.

13. Connect wiring harness (20) to manifold assembly (14) .

14. Install switch assembly (19) to manifold assembly (14). Install two bolts (18). Connect wiring harness (17) .

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Illustration 8	g00817253

15. Position cover (16) and the gasket to manifold assembly (14). Install six bolts (15) that secure cover (16) and the gasket to manifold assembly (14). Install the O-ring seals to the three tubes. Install the three tubes into the side of the manifold assembly. Install three plugs (13) and the O-ring seals that secure the three tubes in manifold assembly (14) .

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Illustration 9	g00817252

16. Install control valve assembly (12) to the selector pressure control valve.

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Illustration 10	g00817328

17. Install ten bolts (10), the washers, and cover (11) to the control valve assembly. Tighten the two bolts (X) to a torque of 48 ± 4 N·m (35 ± 3 lb ft).

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Illustration 11	g00817186

18. Install guard (9) and four bolts (8) to the manifold assembly.

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Illustration 12	g00817152
Top of Transmission Case

19. Attach cover (7) to the transmission case.

20. Attach hose assemblies (6), harness assembly (5), and bracket (4) to cover (7) .

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Illustration 13	g00817049

21. Attach step (1) to the machine.

End By: Install the pressure reducing valve. Refer to Disassembly and Assembly, "Pressure Reducing Valve - Install". This information is in the Disassembly and Assembly manual for the machine systems.