794 AC Off-Highway Truck Caterpillar

• The condition of the oil

• The S·O·S recommendation

When an S·O·S program is not used, the oil change interval is based on the following:

• Every 3000 Service Hours if Caterpillar FDAO/FD-1 oil is used.

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Illustration 1	g03129591

1. Rotate the wheels so that final drive drain plug (1) is in the lowest position on the rear wheel.

2. Prepare the machine for maintenance. Refer to Operation and Maintenance Manual, "Prepare the Machine for Maintenance".
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   NOTICE
   Care must be taken to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting, and repair of the product. Be prepared to collect the fluid with suitable containers before opening any compartment or disassembling any component containing fluids. Refer to Special Publication, NENG2500, "Dealer Service Tool Catalog" for tools and supplies suitable to collect and contain fluids on Cat® products. Dispose of all fluids according to local regulations and mandates.

3. Remove the final drive drain plug. Drain the oil into a suitable container.

   Note: Inspect the magnetic drain plug and the oil. Refer to Operation and Maintenance Manual, "Final Drive Oil - Inspect" for further information.

4. Clean the drain plug. Install the drain plug.

5. Repeat Step 1 through Step 4 for the other final drive.

   Note: The final drives may need to be repositioned to place the drain plug in the lowest position.

6. Remove final drive filler plugs (2). Fill each final drive to the bottom of the filler plug opening. When the final drive drain plug is in the lowest position, the final drive filler plug will be at the correct oil level.

   Note: Allow oil to fill all the compartments. Correct oil levels are critical in the final drives.

7. Operate the machine on level ground at low speed for a few minutes.

   Note: The final drive oil level must be checked and maintained at operating temperature. After the oil has been changed in the final drives, adjustment of the oil level may be necessary when the truck reaches operating temperature.

8. Stop the machine. Check the oil level. If necessary, adjust the oil level to the bottom of the filler plug when the drain plug is in the lowest position.

   Note: Overfilling the final drives will cause overheating and foaming of the oil in long hauling applications and high-speed applications. A reduction of the life of components may be the result of overheating and foaming of the oil.