D7R Series 2 Track-Type Tractor Power Train Caterpillar

Symptoms

Before you complete any procedure, read Troubleshooting, "Troubleshooting Procedures" in this module.

• "System Pressure Is Low"

System Pressure Is Low

1. Check the system pressure.

   ReferenceRefer to Testing and Adjusting, "Relief Valve (Main) - Adjust" that is in this module.

   Note: Do not adjust the pressure of the main relief valve at this time.

   Expected Results

   • The system pressure is correct.

   • The original problem is resolved.

   Results

   • OKAY: Stop.

   • NOT OKAY: Proceed to Step 2.

2. Check the transmission modulating valves.

   1. Check the installation of the transmission modulating valves. Make sure that the valves are installed correctly and that the valves are torqued properly.

   2. If necessary, repair the valves or replace the valves.

   3. Check the system pressure.

      ReferenceRefer to Testing and Adjusting, "Main Relief Valve - Adjust" that is in this module.

      Expected Results

      • The system pressure is correct.

      Results

      • OKAY: Stop.

      • NOT OKAY: The cause of the problem may be the adjustment of the main relief valve. The main relief valve maintains the system pressure in the control section of the power train oil pump. Proceed to Step 3.

3. Adjust the main relief valve.

   ReferenceRefer to Testing and Adjusting, "Main Relief Valve - Adjust" that is in this module.

   Expected Results

   • The main relief pressure is correct.

   • The system pressure is correct.

   Results

   • OKAY: Stop.

   • NOT OKAY: Proceed to Step 4.

4. Inspect the main relief valve.

   1. Disassemble the main relief valve and inspect the valve for failure.

   2. Check the stiffness of the spring.

      ReferenceRefer to Specifications, "Main Relief Valve" in the Service Manual for your machine.

   3. If necessary, repair the valve or replace the valve.

   4. Check the operation of the machine for the original problem.

      Expected Results

      • The original problem is resolved.

      Results

      • OKAY: Stop.

      • NOT OKAY: Proceed to Step 5.

5. Inspect the oil pump.

   1. Disassemble the oil pump and inspect the pump for failure.

   2. Inspect the oil pump drive for failure.

   3. Repair the pump drive or replace the pump drive, if necessary.

   4. Repair the pump or replace the pump, if necessary.

   5. Check the operation of the machine for the original problem.

      Refer to Disassembly and Assembly, "Power Train Oil Pump" in the Service Manual for your machine.

      Expected Results

      • The original problem is resolved.

      Results

      • OKAY: Stop.

      • NOT OKAY: Proceed to Step 6.

6. Inspect the transmission for internal leakage.

   1. Disassemble the transmission and inspect the transmission for leaks.

   2. Check all seals for failure.

   3. Repair the transmission, if necessary.

      ReferenceRefer to Disassembly and Assembly, "Transmission" in the Service Manual for your machine.

      Expected Results

      • The original problem is resolved.

      Results

      • OKAY: Stop.

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