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Старый 03.05.2011, 14:28
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Transmission Clutch Troubleshooting
Symptoms
Before you follow any procedure, read Troubleshooting, "Troubleshooting Procedures" in this module.
• "The Transmission Clutch Is Engaged and the Clutch Does Not Release"
• "The Transmission Clutch Does Not Engage"
The Transmission Clutch Is Engaged and the Clutch Does Not Release
Follow this procedure if the machine seems to have a brake that is applied. Also, follow this procedure if the machine only operates in certain gears.
1. Check the pressures.
a. Start the engine. Operate the engine at high idle.
b. Push down on the service brake pedal in order to engage the brakes.
c. Disengage the parking brake.
d. Shift the transmission into the NEUTRAL position in order to check these clutches: No. 1, No. 2, No. 4 and No. 5. No. 3 clutch should be the only clutch that is engaged.
e. Shift the transmission into FIRST GEAR FORWARD in order to check No. 3 clutch. No. 2 clutch and No. 5 clutch should be engaged.
f. Measure the pressure for the clutch that does not release.
See the procedure in Testing and Adjusting, "Transmission Controls" in this module.
Expected Results
 When the clutches are released, all clutch pressures are less than 138 kPa (20 psi).
Results
 OKAY: Stop. The clutch releases properly.
 NOT OKAY: Proceed to Step 2.
2. Check the bolt torques for the transmission modulating valves.
a. Check the torque of the bolts that hold the transmission modulating valves to the transmission control valve.
ReferenceRefer to Specifications, "Transmission Hydraulic Control Valves" in the Service Manual for your machine.
Expected Results
 The torque for the valves is correct.
Results
 OKAY: Proceed to Step 3.
 NOT OKAY: Tighten the bolts or loosen the bolts to the proper torque. Check the operation of the machine for the original problem. If conditions are not resolved, proceed to Step 3.
3. Replace the transmission modulating valve.
a. Replace the transmission modulating valve for the clutch that does not release.
b. Calibrate the transmission modulating valves.
ReferenceRefer to Machine Electronic Control System, RENR9867, "System Calibrations".
c. Check the operation of the machine for the original problem.
Expected Results
 The original problem is resolved.
Results
 OKAY: Stop.
 NOT OKAY: If the original problem is still present then the cause of the problem is uncertain. Please call technical support with the information that has been gathered.
The Transmission Clutch Does Not Engage
Follow this procedure if the machine does not operate in specific gears.
1. Check the system pressure.
ReferenceRefer to Testing and Adjusting, "Main Relief Valve - Adjust" that is in this module.
Expected Results
o The system pressure is correct.
Results
o OKAY: If the original problem is not resolved proceed to Step 4.
o NOT OKAY: The cause of the problem may be the adjustment of the main relief valve. The main relief valve maintains the system pressure in the control section of the power train oil pump. Proceed to Step 2.
2. Adjust the pressure setting of the main relief valve.
ReferenceRefer to Testing and Adjusting, "Main Relief Valve - Adjust" that is in this module.
Expected Results
o The pressure setting of the main relief valve is correct.
Results
o OKAY: The pressure setting of the main relief valve is correct. If the original problem is not resolved proceed to Step 4.
o NOT OKAY: Proceed to Step 3.
3. Follow the procedure in this reference.
Refer to "System Pressure Is Low" in this module under Troubleshooting, "Oil Pressure Troubleshooting".
Results
o REPAIRED, OK: The original problem is resolved. Stop.
o NOT OKAY: The system pressure is correct but the problem is not resolved. Proceed to Step 4.
4. Check the pressure at the clutch.
a. Start the engine. Operate the engine at high idle.
b. Press down the service brake pedal in order to engage the brakes.
c. Disengage the parking brake.
d. Shift the transmission into a gear that requires the use of the clutch that is not functioning correctly.
ReferenceRefer to Testing and Adjusting, "Transmission Controls" in this module.
e. Measure the pressure at the clutch that does not engage.
Expected Results
 The hydraulic pressure of clutches 1 through 4 is equal to the setting of the main relief valve. The hydraulic pressure of clutch 5 is 2240 kPa (325 psi).
Results
 OKAY: Proceed to Step 8.
 NOT OKAY: Proceed to Step 5.
5. Interchange modulating valves.
a. Interchange one of the modulating valves that should be engaged with one modulating valve that should not be engaged.
b. Determine whether the problem follows one particular valve.
c. Repeat the procedure for all modulating valves that affect the gear that is not functioning properly.
Results
 FOLLOWS: The problem follows one valve. Proceed to Step 6.
 DOES NOT FOLLOW: Proceed to Step 7.
6. Replace the transmission modulating valve.
a. Replace the transmission modulating valve for the clutch that does not engage.
b. Calibrate the transmission modulating valves.
ReferenceRefer to Machine Electronic Control System, RENR9867, "System Calibrations".
c. Check the operation of the machine for the original problem.
Expected Results
 The original problem is resolved.
Results
 OKAY: Stop.
 NOT OKAY: Proceed to Step 8.
7. Restore the modulating valve.
a. Restore the modulating valves to the original locations. Note the suspect valve and the original location.
b. Check the operation of the machine for the original problem.
Expected Results
 The original problem is resolved.
Results
 OKAY: Stop.
 NOT OKAY: Proceed to Step 8.
8. Inspect the clutch.
a. Disassemble the clutch and inspect the clutch for failure.
ReferenceRefer to Disassembly and Assembly, "Transmission" in the Service Manual for your machine.
b. Check for excessive wear on friction discs and clutch plates.
c. Inspect the piston seals.
d. Repair the components or replace the components, if necessary.
e. Check the operation of the machine for the original problem.
Expected Results
 The original problem is resolved.
Results
 OKAY: Stop.
 NOT OKAY: The cause of the problem is uncertain. Please call technical support with the information that has been gathered. Stop.

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