966M and 972M Wheel Loaders Caterpillar

Show/hide table

Personal injury or death can result from sudden machine movement. Sudden movement of the machine can cause injury to persons on or near the machine. To prevent injury or death, make sure that the area around the machine is clear of personnel and obstructions before operating the machine.

Show/hide table

Personal injury can result from hydraulic oil pressure and hot oil. Hydraulic oil pressure can remain in the hydraulic system after the engine has been stopped. Serious injury can be caused if this pressure is not released before any service is done on the hydraulic system. Make sure all of the attachments have been lowered, oil is cool before removing any components or lines. Remove the oil filler cap only when the engine is stopped, and the filler cap is cool enough to touch with your bare hand.

Show/hide table

Escaping fluid under pressure, even a pinhole size leak, can penetrate body tissue, causing serious injury, and possible death. If fluid is injected into your skin, it must be treated immediately by a doctor familiar with this type of injury. Always use a board or cardboard when checking for a leak.

Operational Checks

Operate the machine in each direction and in all speeds. Note the noises that are not normal and find the sources of the noises. If the machine is not operating correctly, refer to the "Troubleshooting Problem List" below.

Make sure that you check for any service codes that have been generated before troubleshooting a problem.

Reference: For more information on checking for service codes with the Cat Monitoring System, refer to the Service Manual module Troubleshooting, "Using Cat Monitoring System to Determine Diagnostic Codes" for the machine that is being serviced.

Reference: For more information on checking for service codes with the Cat Electronic Technician, refer to the Service Manual module Troubleshooting, "Using Cat Electronic Technician to Determine Diagnostic Codes" for the machine that is being serviced.

Troubleshooting Reference

When troubleshooting a hydraulic problem on a 966M or 972M Wheel Loaders, refer to Schematic, KENR5563, "966M and 972M Wheel Loader Hydraulic System".

Troubleshooting Problem List

• Torque converter pressure is high.

• Torque converter pressure is low.

• The torque converter overheats.

Probable Causes of Problems in the Torque Converter

Problem

Torque converter pressure is high

Probable causes

1. There is a restriction inside the torque converter.

2. There is a restriction in an oil passage or in the oil cooler.

3. The inlet relief valve for the converter is stuck in the closed position.

Problem

Torque converter pressure is low

Probable causes

1. The inlet relief valve in the converter is stuck in the open position.

2. Adjustment of torque converter outlet relief valve is not correct.

3. The valve spool in torque converter outlet relief valve does not move.

4. Pump flow or oil pressure is low. This issue may be caused by any of the following conditions:

   1. Low oil level

   2. A restriction in the oil flow circuit or a dirty oil strainer.

   3. Oil pump failure.

   4. Air leaks on the inlet side of the pump.

   5. Leakage inside the transmission (worn seals around the clutch piston).

Problem

The torque converter overheats

Probable causes

1. The machine is being used for the wrong application. There is too much torque converter slip, which is caused by too much load.

2. Incorrect transmission gear is being used for the load that is on the machine. Shift to a lower gear.

3. The oil level in the transfer gear case is incorrectly high or low.

4. The coolant level in the engine radiator is low.

5. The oil cooler or oil lines are restricted.

6. Oil flow through the torque converter is too low. This issue may be caused by any of the following conditions:

   1. The inlet relief valve in the converter is bypassing too much oil flow.

   2. Pump flow or oil pressure is low. Refer to the Problem: Torque converter pressure is low.