PL72 Pipelayer Caterpillar

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Hot oil and components can cause personal injury. Do not allow hot oil or components to contact skin.

Drain the Oil

High Speed Oil Change

Operate the machine in order to warm the power train oil. The machine must be level.

Open the hinged engine access door on the left-hand side of the machine. Then, lift and remove the lower access door to the engine compartment.

The high speed oil change connection fittings are mounted on the left-hand frame rail near the rear of the engine access opening.

Illustration 1	g03745903
(1) Power train high speed oil change connection fitting (2) Engine high speed oil change connection fitting (reference only)

Power train high speed oil change connection fitting (1) and a 126-7538 Nozzle can be used with additional equipment to change the power train system oil.

This arrangement removes oil from the sump in the bevel gear case. The high speed oil change does not remove oil from the torque converter or from the transmission case.

The power train system oil filter will still need to be changed. See the Operation and Maintenance Manual, "Power Train Oil Filter - Replace" in this manual for the procedure to change the filter.

Conventional Oil Change

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Illustration 2	g03745938
Bevel gear case drain valve (3) Drain plug

1. Remove plug (3) from the drain valve in the bevel gear case. Install a 4C-8563 Swivel into the valve. Clamp a hose to the swivel. A 25.4 mm (1 inch) pipe and hose can be used. Use a 25.4 mm (1 inch) pipe with 1-11 1/2 NPTF threads. Do not tighten the pipe.

2. Place a suitable container below the drain hose. Turn the swivel or pipe clockwise to open the internal drain valve and allow the oil to drain into the container.

3. Lower the rear bottom guard to gain access to bottom of the torque converter.
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   Illustration 3	g03745951
   Torque converter drain valve (4) Drain plug (5) Drain valve

4. Remove plug (4) from the drain valve for the torque converter. Install a 12.7 mm (.5 inch) pipe into the drain valve. Use a 12.7 mm (0.50 inch) pipe with 1/2-14 NPTF threads.

5. Clamp a hose to the pipe in order to drain the oil into a suitable container.

6. Open drain valve (5) and drain the oil into the container.
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   Illustration 4	g03745969
   Transmission drain valve (6) Drain plug (7) Drain valve

7. Remove plug (6) from the bottom of the drain valve at the rear of the transmission cover. Install a 12.7 mm (.5 inch) pipe into the drain valve. Use a 12.7 mm (0.50 inch) pipe with 1/2-14 NPTF threads. Clamp a hose to the pipe to drain the oil into a suitable container.

8. Open drain valve (7) and drain the oil into the container.

9. Allow oil to drain completely from the power train components of the machine.

10. Close drain valve (5) on the torque converter. Close drain valve (7) at the rear of the transmission cover.

11. Remove the hoses and remove the pipes from the torque converter drain valve and the transmission drain valve.

12. Remove the swivel and the hose, or remove the pipe and the hose, from the drain valve in the bevel gear case. The internal drain valve will close.

13. Clean the oil drain plugs and install the oil drain plugs.

14. Properly dispose of the used power train oil.

Clean Screens

Screens should be removed and cleaned when the oil is drained. Drain the oil into a suitable container before removing any screen.

Inspect all components that are removed during this maintenance procedure for wear or for damage. Replace all components that show signs of wear or show signs of damage.

Torque Converter Scavenge Screen

Note: Service the torque converter scavenge screen only when the oil has been drained from the torque converter.

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Illustration 5	g03745999
(8) Scavenge line

1. Remove torque converter scavenge line (8) from the torque converter.
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   Illustration 6	g03746019
   (8) Scavenge line (9) Scavenge screen

2. Remove scavenge screen (9) from the torque converter housing.

3. Wash the screen in a clean, nonflammable solvent.

4. Inspect the seal. If the seal is damaged, replace the seal.

5. Install the screen. Install the torque converter scavenge line.

Bevel Gear Case Magnetic Suction Screen

Note: Service the bevel gear case magnetic suction screen only when the oil has been drained from the bevel gear case.

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Illustration 7	g03747960
Bevel gear case magnetic suction screen assembly

1. Locate the bevel gear case magnetic suction screen assembly. This assembly is mounted on the front of bevel gear case near the right-hand frame rail.
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   Illustration 8	g03748188
   Components of bevel gear magnetic suction screen assembly (10) Hose (11) Adapter (12) Cover assembly (13) Wave washer (14) Screen assembly (15) Magnet tube assembly (16) Screen housing

2. Place a suitable container below the outer end of the bevel gear magnetic suction screen assembly.

3. Loosen clamp on hose (10), and carefully remove the hose from adapter (11) on the end of cover assembly (12).

4. Rotate the cover assembly in the counterclockwise direction to release the retaining tabs on the cover assembly from screen housing (16). Pull the cover assembly from the screen housing.

5. Collect wave washer (13) and retain the wave washer for reassembly of the screen assembly.

6. Remove screen assembly (14) and magnet tube assembly from screen housing (16).

7. Wash the screen assembly and the magnet tube assembly in a clean, nonflammable solvent.

8. Install the magnet tube assembly and the screen assembly.

9. Clean the cover assembly and the O-ring seal for the cover assembly. Inspect the cover assembly for damage. Replace the cover assembly, if necessary.

10. Inspect the O-ring seal for damage. Replace the O-ring seal, if necessary.

11. Install the wave washer, then install the cover assembly. Rotate the cover assembly in the clockwise direction to engage the retaining tabs on the cover assembly with the screen housing.

12. Install the hose on the adapter and secure the hose with the clamp.

Transmission Suction Screen

Note: Service the transmission case suction screen only when the oil has been drained from the transmission case.

Illustration 9	g03746173
(10) Transmission drain valve assembly

1. Remove transmission drain valve assembly (10) from the rear of the transmission cover.
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   Illustration 10	g03746182
   (11) Transmission suction screen

2. Remove transmission suction screen (11) from the transmission cover.

3. Clean the suction screen and the drain valve assembly in clean, nonflammable solvent.

4. Inspect the O-ring seal for the drain valve assembly. If the seal is damaged, replace the seal.

5. Install the suction screen, and then install the drain valve assembly.

Fill With Oil

The power train system oil level gauge and the power train system oil filler cap are located in a compartment forward of the left-hand ROPS post.

Open the access door that is forward of the left-hand ROPS post to fill the power train system with oil and to check the power train system oil level.

Illustration 11	g03746191
(12) Filler cap (13) Oil level gauge

1. Remove oil filler cap (12).

2. Fill the bevel gear case with oil. See Operation and Maintenance Manual, " Capacities (Refill)".

3. Always measure the oil with oil level gauge (13). See Operation and Maintenance Manual, "Power Train System Oil Level - Check" for more information.

4. Clean the oil filler cap and install the oil filler cap.

5. Start the engine and operate the machine for a short time. Park the machine and recheck the power train system oil level. Add oil, if necessary.

For additional information about power train system oil, see Special Publication, SEBU6250, "Caterpillar Machine Fluids Recommendations" or consult your Cat dealer.