The Transmission Jerks When Lock-Up Engages
The gearbox jerks when lock-up engages
Checking for the fault
Has the customer complained of vibrations?
Yes - Checking oil quality and oil level in transmission
No - Fault-tracing without result
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Checking oil quality and oil level in transmission
Note! Transmission fluid quality and level are extremely important for the function of the transmission. Therefore it is imperative that these are correct. In addition the oil level is dependent on oil temperature.
- Ignition on.
- Read off the oil temperature.
Check the oil level. If the oil level is low, check the transmission for leakage, then top up with oil.
Check the oil's quality.
If the oil smells burnt, change transmission oil.
Check the transmission fluid for metal swarf. Take a sample using the dip stick.
Replace the transmission if the transmission fluid contains metal swarf.
Other information:
- Gearbox fluid, replacing Transmission Fluid, Replacing
- Oil level, checking Checking Oil Level
- Oil grade, checking Oil Grade, Checking
Select an alternative below:
1. No defect found.
2. Transmission oil changed, level low or quality poor.
3. The transmission fluid contains metal swarf.
1 - Checking the cooling system
2 - Resetting the oil quality counter
3 - Replacing the gearbox
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Checking the cooling system
- Perform the following check.
Test pressurization Testing and Inspection
Does the pressure drop?
Yes - Checking the cooling system
No - Checking software
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Replacing the gearbox
Earlier tests indicate that there is a fault in the transmission.
Replace transmission. See:
Gearbox, removing Transmission, Removing
Transmission, installing Transmission, Installation
Continue - Resetting adaptation and the fluid quality counter
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Checking software
Check that the control module has the latest version of the relevant software.
- If new software is available, download to the control module and then select Continue.
- If the control module already has the latest software select Continue.
Continue - Test driving the transmission
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Resetting the oil quality counter
Resetting Transmission fluid change counter
Resetting Transmission fluid change counter
Hint: The transmission control module (TCM) has a counter for the oil quality. The counter counts up if the transmission is exposed to too high a load or an ambient temperature that is too high. If the counter is not reset when the oil is drained or changed, there is a risk that a diagnostic trouble code (DTC) will be stored in faulty circumstances. Therefore it is important that the "Transmission oil change" counter is reset.
Note! This applies only when the transmission fluid is changed and when the fluid is changed when repairs are carried out to the transmission temperature sensor.
- Ignition on.
Reset the counter by clicking on the VCT 2000 symbol.
Continue - DONE
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DONE - Verification
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Resetting adaptation and the fluid quality counter
Resetting the adaptation
Resetting adaptation and the counter for "Transmission oil change"
Hint: The transmission has torque controlled adaptive pressure control. Pressure control means that the transmission regulates the pressure itself during each gear shift. This avoids harsh gear shifting. Each gear shift is evaluated by the control module and stored in the memory. This allows for compensation for wear and tear in the transmission and clutch. It is important that the adaptation in the memory is reset after the transmission has been repaired. This is to ensure normal operation. The oil is replaced during repair; the "Transmission oil change" counter must be reset. If the counter is not reset when the fluid is drained and replaced, there is a risk that a diagnostic trouble code (DTC) will be stored in incorrect circumstances.
Note! This applies only if the transmission or one of the components in the transmission have been replaced.
- Ignition on.
Click on the VCT2000 symbol to reset the adaptation and counter.
Continue - DONE
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DONE - Verification
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Verification
Verification
Hint: After carrying out the repair, check that the fault has been remedied.
- Ignition off.
- Reconnect the connectors, reinstall components etc.
- Ignition on.
Test drive the vehicle following:
Test-drive schedule TCM-002E AW55-50/51SN, AW55-50/51SN Test-Drive Schedule
During the test drive the oil temperature must be above 20°C.
Look out for any irregularities in the function of the transmission.
Is the transmission operating correctly?
Yes - VERIFIED
No - VERIFICATION FAILEDPAPER
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VERIFICATION FAILED - Troubleshooting information
VERIFIED - Fault Found
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Troubleshooting information
Information
Fault-tracing information
The fault should have been detected and remedied. As this is not the case fault-tracing has failed.
Exit fault-tracing for this diagnostic trouble code (DTC) or make another attempt.
Do you want to exit fault-tracing?
Yes - FAULT-TRACING FAILED
No - Attempt New Test
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FAULT-TRACING FAILED - FAULT-TRACING FAILED
Attempt New Test - Checking for the fault
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Fault-tracing without result
The diagnostic trouble code (DTC) indicates that a fault occurred previously but that the fault is no longer present.
No further corrective action is required if the diagnostic trouble code (DTC) is intermittent and does not recur.
Select "Continue" to exit.
Continue - No Fault Found
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Checking the cooling system
Ensure that the leak is the cause of the coolant coming in contact with the transmission oil by checking the quality of the oil.
If the quality of the transmission fluid had deteriorated due to leakage from the cooling system, replace the transmission, radiator, hoses and expansion tank as below.
Other information:
- Oil grade, checking, B5254T2, AW55-50/51SN, B5254T2, AW50/51 AWD Oil Grade, Checking
- Gearbox, removing Transmission, Removing
- Installing the gearbox Transmission, Installation
- Radiator / charge air cooler (CAC), replacement
Select "Continue" when you are ready.
Continue - Resetting adaptation and the fluid quality counter
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Replacing the torque converter
- Ignition off.
Replace the torque converter.
Remedy as necessary.
Other information
- Replacing the sealing ring for the oil pump Replacing the Sealing Ring For the Oil Pump
Continue - REPAIRED
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Test driving the transmission
Test drive schedule, description Test Drive Schedule, Description Test drive schedule, description, B5244T5, AW55-50/51SN, B5254T2, AW55-50/51SN, B5254T2, AW50/51 AWD Test Drive Schedule, Description
Was any corrective action taken?
Yes - DONE
No - Replacing the torque converter
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