D8T and D9T Track-Type Tractors Caterpillar

Probable Causes

• The power train oil level is low.

• The power train oil pump has a failed fitting, a failed hydraulic hose, or a failed hydraulic line on the inlet side.

• The scavenge screen has an obstruction.

Recommended Actions

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Personal injury can result from hot oil spray and raised work tools. Make sure all the work tools have been lowered, the oil is cool and the pressure has been released from the hydraulic system before removing any components or lines. Do not allow hot oil or components to contact skin.

Follow this procedure if the oil is foaming in the power train oil system. The oil could also be discolored. A small amount of air in the power train oil is normal.

Note: Care must be taken in order to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting, and repair of the machine. You must be prepared to collect the fluid with suitable containers before opening any compartment or disassembling any component that contains fluid. Dispose of all fluids according to local regulations.

The Power Train Oil Level Is Low

Ensure that the power train oil level is between the "OPERATING ZONE" marks on the dipstick.

Reference: Refer to (D8T) Operation and Maintenance Manual, SEBU9087, "Power Train Oil Level - Check".

Reference: Refer to (D9) Operation and Maintenance Manual, SEBU8550, "Lubricant Viscosities" and Operation and Maintenance Manual, SEBU8736, "Refill Capacities".

Check the operation of the machine for the original problem.

Expected Results

• The original problem is resolved.

Results

• OKAY: Stop.

• NOT OKAY: If conditions are not resolved, proceed to "The Power Train Oil Pump Has A Failed Fitting, A Failed Hydraulic Hose Or A Failed Hydraulic Line On The Inlet Side".

The Power Train Oil Pump Has A Failed Fitting, A Failed Hydraulic Hose Or A Failed Hydraulic Line On The Inlet Side

1. Check the hydraulic lines and check the fittings on the inlet side of the power train oil pump for leaks. Air may be drawn into the system from the suction side of a circuit during operation if the lines, hoses, or connections are damaged.

   1. Check the lines and check the fittings on the inlet side of the power train oil pump for leaks. Repair components and/or replace components, if necessary.

      Expected Results

      • The original problem is resolved.

      Results

      • OKAY: Stop.

      • NOT OKAY: Repair all leaks that are found. Check the operation of the machine for the original problem. If conditions are not resolved, proceed to "The Scavenge Screen Has An Obstruction".

The Scavenge Screen Has An Obstruction

1. Remove the screens that are in the inlet passage of the scavenge pump.

   Each inlet to the scavenge section of the pump contains a screen.

2. Check the screens for obstructions. Check the filter element for foreign material. Use a magnet in order to separate ferrous particles from nonferrous particles.

3. Replace the screens.

4. Start the engine.

5. Stop the engine.

6. Obtain an oil sample.

   Reference: Refer to Operation and Maintenance Manual, SEBU8550, "S·O·S Information".

Expected Results

• The original problem is resolved. The air has been removed from the oil system.

Results

• OKAY: Stop.

• NOT OKAY: The cause of the problem is uncertain. Call technical support with the information that has been gathered.