If the engine speed is lower than the normal given speed or if the engine speed is higher than the normal given speed, this indicates that there is a problem in the engine or in the transmission. If testing shows that the engine performance is correct and the torque converter stall speed is not correct, the problem is in the torque converter or in the transmission.
The service brakes must be applied when tests are performed. Make sure that the service brakes are fully operational before you perform any tests. Make sure that the transmission oil is at the normal operating temperature of 82 to 93°C (180 to 200°F).
The drive wheels must not turn during the torque converter stall test. Place the machine in position against a solid, stationary object such as a loading dock. Engage the parking brake.
ReferenceIn order to check the performance of the Caterpillar 3126 Engine, refer to Specifications, SENR3582, "3126 Engine For Caterpillar Built Machines" and Systems Operation/Testing and Adjusting, SENR3583, "3126 Engine For Caterpillar Built Machines".
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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. |
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Before you start the test procedure, complete the following procedure.
- Machine Preparation for Troubleshooting
ReferenceFor additional information on preparing the machine for troubleshooting, refer to Testing and Adjusting, "Machine Preparation for Troubleshooting" for the machine that is being serviced.
- Move the machine to a level area that is clear of personnel.
- Move the transmission direction control switch to the NEUTRAL position. Apply the parking brake.
- If the torque converter stall test is done indoors, make sure that there is adequate ventilation for the exhaust.
- Start the engine.
Note: To ensure that the transmission oil does not overheat, do not keep the torque converter in a full stall condition for more than 30 seconds.
- Make sure that the transmission oil is at normal operating temperature.
- Press operator mode switch (1) until display (2) of the Caterpillar Monitoring System displays the rpm of the engine.
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| Illustration 1 | g00564939 |
View of Left side of the Dash (1) Operator mode switch. | |
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| Illustration 2 | g00703524 |
View of Dash (2) Display. | |
- Apply the service brakes firmly and keep the brakes applied through Step 10.
- Disengage the parking brake. Shift the transmission direction control switch and the transmission upshift switch to fifth speed forward and fully depress the accelerator pedal. Allow the engine rpm to stabilize. Then, observe the rpm on the display.
- The correct stall speed is 2060 ± 75 rpm for the 525B Wheel Skidder. The correct stall speed is 1990 ± 75 rpm for the 535B Wheel Skidder.
- After the torque converter is stalled, shift the transmission direction control switch to the NEUTRAL position and operate the engine at 1200 rpm to 1500 rpm in order to cool the oil.
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To prevent the transmission oil from getting too hot, do not keep the torque converter at full stall for more than 30 seconds. If transmission oil becomes too hot, perform the procedure that follows to cool the oil. |
Stall speeds that are low indicate that engine performance is not correct. Stall speeds that are high indicate that transmission performance is not correct or that the performance of the torque converter is not correct. If you must repeat the test, keep the transmission in neutral and wait for two minutes between tests.
ReferenceFor additional information about troubleshooting the transmission and troubleshooting the torque converter, refer to Testing And Adjusting, "Power Train Troubleshooting" for the machine that is being serviced.
ReferenceFor additional information about the Caterpillar Monitoring System, refer to Systems Operation/Testing and Adjusting, SENR1394, "Caterpillar Monitoring System" for the machine that is being serviced.