2001/03/05 Caterpillar

Landfill Compactors:

836G (S/N: 7MZ1-UP)

Wheel Loaders:

988G (S/N: 2TW1-UP)

992G (S/N: 7HR1-UP; ADZ1-UP)

994 (S/N: 9YF1-UP)

994D (S/N: 3TZ1-UP)

Wheel Tractors:

834G (S/N: 6GZ1-UP)

854G (S/N: 1JW1-UP; AMP1-UP)

Service Manual module, RENR3095-02, "Testing and Adjusting, 988G Wheel Loader Power Train", "Torque Converter Troubleshooting"Service Manual module, SENR1347-03, "Testing and Adjusting, 992G Wheel Loader and 854G Wheel Tractor Power Train", "Torque Converter Troubleshooting"Service Manual module, RENR2506, "Testing and Adjusting, 994D Wheel Loader Power Train", "Torque Converter Troubleshooting"Service Manual module, SENR4745-01, "Testing and Adjusting, 994 Wheel Loader Power Shift Transmission", "Torque Converter"Service Manual module, RENR2182-01, "Testing and Adjusting, 834G Wheel Tractor and 836G Landfill Compactor Power Train", "Torque Converter Troubleshooting"

The calibration of the impeller clutch can generate error messages if a problem is encountered during calibration. The following information is used to aid in troubleshooting the problem that was based on the error message. The information should be added to the material that was referenced above.

Table 1

Troubleshooting Information for the Calibration of the Impeller Clutch
Error Message	Probable Causes	Possible Corrective Actions
Torque converter output speed is low.	Engine speed is too low.	Use the throttle lock to set the engine speed above the following minimum values: 2050 rpm (988G,834G,836G) 1650 rpm (992G,994D,854G)
	Speed sensor problem	Check for fault codes on the torque converter output speed sensor. Check the sensor connector. Adjust or replace the sensor, if necessary.
	Impeller clutch pressure is too low.	Check valve function. Check the connector. Check ECM output. Check the converter for excessive leakage in the circuit for the impeller clutch.
	Damaged impeller clutch	Check transmission screens. Inspect the impeller clutch.
	Excessive drag in transmission	Check transmission screens. Inspect the impeller clutch.
Torque converter output speed is high.	Speed sensor problem	Check for fault codes on the torque converter output speed sensor. Check the sensor connector. Adjust or replace the sensor, if necessary.
	Engine speed is too high.	Adjust the engine high idle speed.
The speed change of the torque converter is in the low range.	Speed sensor problem	Check for fault codes on the torque converter output speed sensor Check the sensor connector. Adjust or replace the sensor, if necessary.
	Impeller clutch pressure is too low.	Check valve function. Check the solenoid connector. Check ECM output. Check the converter for excessive leakage in the circuit for the impeller clutch.
	Drag in the lockup clutch.	Check for residual pressure in the circuit for the lockup clutch. Check the screens in the transmission for material from the clutch. Inspect the lockup clutch for damaged discs or damaged plates. If the lockup clutch has new discs, operate the machine and engage the lockup clutch several times. Repeat the calibration.
	Excessive drag in the transmission	Check the screens in the transmission for material from the clutch. Inspect the transmission for warped direction clutches or damaged direction clutches.
Hold pressure is too high.	Impeller clutch pressure is out of tolerance.	Check valve function. Check the solenoid connector. Check the ECM output. Check the converter for excessive leakage in the circuit of the impeller clutch. Check for high torque converter inlet pressures and outlet pressures. Check the PTO system which is downstream of the converter for restrictions.
Hold pressure is too low.	Impeller clutch pressure is out of tolerance.	Check valve function. Check the solenoid connector. Check ECM output.
Hold pressure inconsistent	Impeller clutch pressure is not responding properly.	Check valve function. Check the solenoid connector. Check ECM output. Check the converter for excessive leakage in the circuit of the impeller clutch. Check the transmission screens for debris.