980M and 982M Wheel Loaders Power Train, Steering, Braking, Hydraulic, and Machine Systems Caterpillar

Introduction

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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.

The following procedure is used in order to test the torque converter stall test.

Note: Insure that the transmission oil is at normal operation temperature. Machines operating under normal conditions should have engine stall speeds that are within the specified range. Refer to the factory test measurements in order to determine the appropriate specification for the machine that is being serviced. If the machine that is being serviced is outside the range of engine stall speeds, the power train components should be inspected. Use the component test specifications in order to determine the corrective action. These ranges of engine stall speed should not be used to adjust the engine power of the machine. If engine output is suspect, the engine should be tested on a dynamometer.

The torque converter stall test helps determine if the engine is producing the correct power output. The torque converter stall test provides an engine speed for comparison with the torque converter stall speed that is measured at the factory. The engine stall speed should be in the range that is shown.

The torque converter stall test helps determine if the engine is producing the correct power output. This stall test is used in many diagnostic procedures.

The parking brake must be applied when the tests are performed. Make sure that the parking brake is fully operational before you perform any tests.

The service brakes must be applied when the tests are performed. Make sure that the service brakes are fully operational before you perform any tests.

Machine Preparation

1. Position the machine on a smooth horizontal location.

2. Ensure that the parking brake is in engaged.

3. Ensure that the work tool is positioned on the ground.

Reference: For more information about preparing a machine for troubleshooting, refer to the Service Manual module Testing and Adjusting, "Machine Preparation for Troubleshooting".

Test Procedure for Torque Convertor Stall

1. Run the engine and warm the machine to operation temperatures. Engine coolant and hydraulic oil should be at normal machine testing temperatures.

   Note: Warm transmission oil and torque converter oil to the temperatures listed in table.

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   Table 1

   Oil at Normal Operating Temperature
   Transmission Oil	Torque Converter Oil
   83° ± 7°C (181° ± 12°F)	93° ± 17°C (199° ± 30°F)

   • Ensure that the parking brake is engaged. Select manual shift mode. Shift transmission to FOURTH SPEED, NEUTRAL.

2. Shift the transmission to FOURTH SPEED, FORWARD, and press throttle pedal to 100%.

3. A warning indicating that the machine is in gear with parking brake applied will appear on the display.

4. Once the engine speed stabilizes, record engine speed.

5. Shift the transmission to FOURTH SPEED, NEUTRAL, and release throttle pedal.
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   Table 2

   Stall Speed
   Stall speed for the 980M		Stall speed for the 982M
   1973 +10 - 65 rpm		1847 +10 - 65 rpm

   If the torque converter stall speed is too high, the engine power output could be too high. (Not likely)

   If the torque converter stall speed is too low, the engine may not be developing full power. There may be a parasitic load on the engine.

Test Procedure for Torque Convertor Double Stall

1. Run the engine and warm the machine to operation temperatures. Engine coolant and hydraulic oil should be at normal machine testing temperatures.

   Note: Warm transmission oil and torque converter oil to the temperatures listed in table.

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   Table 3

   Oil at Normal Operating Temperature
   Transmission Oil	Torque Converter Oil
   83° ± 7°C (181° ± 12°F)	93° ± 17°C (199° ± 30°F)

   • Ensure that the parking brake is engaged. Select manual shift mode. Shift transmission to FOURTH SPEED, NEUTRAL.

2. At low idle shift the transmission to FOURTH SPEED, FORWARD.

3. Fully place the bucket in the racked back position.

4. Place engine in HIGH IDLE.

5. Stall tilt fully in the racked back position, and command full lift.

6. Once the engine speed stabilizes, Record the stabilized engine speed that occurs when the lift cylinders are extending.

7. Shift the transmission to FOURTH SPEED, NEUTRAL, and release throttle pedal.
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   Table 4

   Double Stall Speed
   Stall speed for the 980M		Stall speed for the 982M
   1438 ± 100 rpm		1454 ± 100 rpm

   If the torque converter double stall speed is too high, the engine power output could be too high. (Not likely)

   If the torque converter double stall speed is too low, the engine may not be developing full power. There may be a parasitic load on the engine.