834G Wheel Dozer and 836G Landfill Compactor Power Train Caterpillar

If the pressure for engagement of lockup clutch is not correct, the life of the lockup clutch can be greatly affected. Use submode 27 to set the pressure of the clutch. In this process, the service technician adjusts the electrical current that is sent to this clutch solenoid valve in order to obtain the pressure for the engagement of lockup clutch that is specified.

The lockup clutch system must be calibrated if any of the following conditions have occurred:

• A solenoid valve has been replaced or cleaned.

• A different power train ECM has been installed.

• A lockup clutch has been rebuilt.

• The power train ECM is flashed and a 679F13 fault is active.

During the calibration of the pressure for the transmission clutch engagement, error codes EXX can occur. The error codes will appear in the display area of the Caterpillar Monitoring System. The error codes will appear if a problem occurs during the calibration. Check the error codes in Table 2.

Calibration Procedure for Engagement of Torque Converter Lockup Clutch

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. Prevent possible injury by performing the procedure that follows before working on 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.

1. Park the machine on a smooth, level surface.

2. Shift the transmission direction switch to the NEUTRAL position. Shift the transmission speed switch to any speed position.

3. Lower the blade or the work tool to the ground.

4. Engage the parking brake.

5. Place blocks in front of the wheels and behind the wheels.

6. Install the steering frame lock.

7. Shut off the engine.

8. Allow only authorized personnel on the machine. Keep unauthorized personnel off the machine and in clear sight of the operator.
   Show/hide table

   Table 2

   Required Tools
   Part Number	Description	Quantity
   4C-8195	Control Service Tool	1
   1U-5481  (1)	Pressure Gauge Group	1
   1U-5482	Hoses From the Pressure Adapter Group	6

   Show/hide table

   ( 1 )

   The 198-4240 Pressure Indicator Tool Gp is also available.

Note: The steps of this procedure must be performed exactly, as described below. This procedure may terminate if any unknown functions or any unexpected functions are activated. This procedure may terminate if a fault (CID FMI) is present. Do not move any switch positions, any levers or any pedals unless you are instructed differently.

Show/hide table



Illustration 1	g00685895
Torque Converter (1) Torque Converter Lockup Clutch (2) Pressure Tap for Lockup Clutch

1. Install a hose from 1U-5482 Pressure Adapter Group to pressure tap (2) .

Show/hide table



Illustration 2	g00685910
(3) 1U-5481 Pressure Gauge Group

2. Attach the opposite end of the hose assembly to the 0 to 3400 kPa (0 to 580 psi) pressure gauge in the 1U-5481 Pressure Gauge Group (3) .

Show/hide table



Illustration 3	g00685912
Command Control Steering (4) Upshift/downshift switch. (5) Transmission direction selector.

Show/hide table



Illustration 4	g00685913
STIC Steering Control (4) Upshift/downshift switch. (5) Transmission direction selector.

3. Make sure that transmission direction switch (5) is in the NEUTRAL position.

4. Make sure that the parking brake is engaged.

5. Start the engine.

6. Warm the transmission oil to approximately 40 °C (104 °F).

   Note: The transmission oil temperature gauge should be at the center position.

7. Start the engine and operate the engine at low idle.

Note: If a new clutch solenoid modulating valve was installed, shift the transmission for at least 12 times into a speed or a direction that uses the clutch solenoid modulating valve. Refer to Illustration 1 in order to identify the clutch solenoid modulating valve and the corresponding clutch. Allow sufficient time for the corresponding clutch to be fully pressurized.

8. Increase the engine speed to high idle.

   Note: You can use the SET/DECEL switch to maintain the high idle. The RESUME/ACCEL switch can be used to resume high idle.

   Show/hide table

   Table 3

   Clutch Engagement Calibration Submode
   Submode 27	Lockup Clutch Engagement

9. Use the 4C-8195 Control Service Tool to enter Transmission Calibration Mode 6. Then enter submode 27. Enter the submode by using the "SCROLL" switch.
   Show/hide table

   Table 4

   Torque Converter Lockup Clutch Engagement Pressure Specifications
   Model	Lockup Clutch
   834G	1720 kPa (250 psi)
   836G	1720 kPa (250 psi)

10. If all the conditions are correct for calibration, the pressure for the clutch is shown in the display area of the Caterpillar Monitoring System. The unit of the value that is displayed is shown in one-tenth of kPa. Multiply the value that is shown in the display by 10 to determine the true specified value in kPa. Record the value.

    In the remaining steps, adjustments are made so that this pressure is the actual pressure gauge reading. The pressure is also listed in Table 5.

    Note: If the conditions are not correct for calibration, the pressure is not shown in the display area. Instead, an error code (EXX) appears. The calibration will not run until all necessary conditions are met. Correct the error code and perform these procedures again. Refer to Table 2 for a list of the error codes and the meaning of the error codes.

11. When all conditions are met and the pressure is shown in the display area, shift transmission direction control switch (5) to the FORWARD position. This pressurizes the torque converter lockup clutch.

12. The value that is shown in the display area will change and a number that corresponds to the electrical current of the particular clutch solenoid modulating valve is shown. The INCREMENT (+) and DECREMENT (-) positions of the "CLEAR" switch can now be used to adjust the electrical current of the clutch solenoid modulating valve. The electrical current of the clutch solenoid modulating valve controls the pressure.

    While you are observing the pressure gauge that was installed in Step 2, use the "CLEAR" switch in order to adjust the pressure of engagement until the pressure gauge reading matches the pressure of engagement from Table 5.

13. Shift the transmission direction control switch to the NEUTRAL position. This completes the calibration of the selected clutch.

14. To exit this submode, use the "SCROLL" switch to scroll to the next submode, or exit Transmission Calibration Mode by using the "MODE" switch.