The hydraulic fan must be at maximum speed when you perform the stall test. This will ensure that there is a consistent parasitic load on the engine. The Caterpillar Electronic Technician (ET) should be used in order to set the fan to maximum speed.
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Personal injury or death can result from machine movement. When tests and adjustments are made to the transmission or the torque converter, the parking brake must be disengaged. To prevent movement of the machine and personal injury perform the procedure that follows. |
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- Move the machine to a level area.
- Engage the parking brake.
- Shift the transmission to the NEUTRAL position.
- Start the engine. Warm the transmission oil to normal operating temperature of approximately 49 to 65°C (120 to 150°F).
- Place the bucket or the blade flat on the ground.
- Connect Caterpillar ET to the data link connector. The data link connector is next to the keypad. Start Caterpillar ET.
- Select "3508B 992G". Select "Diagnostics and Diagnostic tests". Select "Override Parameters and Engine Fan Bypass".
- Enter "0%" for the "Engine Fan Bypass Override Parameter". This should cause the fan to run at maximum speed when the engine is at high idle.
- Release the parking brake.
- Fully depress the right side service brake pedal. Hold the brake pedal in the depressed position for the duration of this test.
- For the 992G Wheel Loader, place the reduced rimpull on/off switch in the Maximum Rimpull position.
- Increase the engine speed to high idle.
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To make sure that the transmission oil does not overheat, do not keep the torque converter in a stall condition for more than 30 seconds. After the torque converter stall test, reduce engine speedto low idle, move the transmission control to neutral and increase the engine speed to approximately 1500 rpm to cool the oil. |
- Place the transmission in FIRST SPEED.
- Move the transmission direction switch to the FORWARD position.
- Allow the engine rpm to stabilize. Record the engine rpm.
- Reduce the engine speed to low idle. Shift the transmission to the NEUTRAL position.
- Use Caterpillar ET in order to reset the "Engine Fan Bypass Override Parameter".
- Exit the Caterpillar ET program and disconnect ET from the machine.
- Allow the engine coolant and the transmission oil to cool. Stop the engine.
| (1FWD) Torque Converter Stall Speeds (1) | |||
| Machine | Minimum | Nominal | Maximum |
| 992G (2) | 1595 RPM | 1625 RPM | 1655 RPM |
| 854G | 1555 RPM | 1585 RPM | 1615 RPM |
| ( 1 ) | Check the stall speed with the hydraulic fan at maximum speed. |
| ( 2 ) | The position of the boom must be below horizontal to the ground in order for the axle protection mode to be active. |
The torque converter stall speed should be within the minimum and maximum engine speeds that are listed in table 1.
If the torque converter stall speed is above the maximum engine rpm one or more of the following conditions exist.
- The axle protection mode is not active.
- The engine power output could be too high.
- The torque converter could have excess slippage.
If the torque converter stall speed is below the minimum engine rpm, the engine may not be developing full power or there may be an excessive parasitic load on the engine.