The Transmission Jerks When Lock-Up Engages
The transmission jerks when lock-up engages
Checking the oil quality and the oil level in the transmission
Note! Transmission fluid quality and level are extremely important for transmission function. 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 the oil.
Check the quality of the oil.
Replace the transmission fluid if the fluid smells burnt.
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:
- To replace the transmission fluid, see Oil, changing, AW55-50/51SN Changing Oil
- To check the level, see Checking and adjusting the oil, AW55-50/51SN Checking Oil Level
- To check the quality of the transmission fluid, see Oil, Quality Check.
Select an alternative below:
1. No fault detected
2. Transmission fluid replaced, the level was low or quality was poor
3. The transmission fluid contains metal swarf.
1 - Checking noise in the transmission
2 - Resetting the oil quality counter
3 - Replacing the transmission
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Checking noise in the transmission
- Test drive the car according to Test drive schedule, description, AW55-50/51SN Test Drive Schedule, Description
- Check for noise from the transmission. Check for jerks in the transmission when lock-up engages.
Is the function of the transmission OK?
Yes - No Fault Found
No - Replacing the transmission control system
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Replacing the transmission
Earlier tests indicate that there is a fault in the transmission.
Replace the transmission according to Replacing the transmission, AW55-50/51SN Replacing The Transmission.
Continue - Resetting the adaptation and oil quality counter
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Replacing the transmission control system
The previous tests indicate that there is a fault in the transmission control system.
Try a new control system according to Replacing the solenoids and control system, AW55-50/51SN Service and Repair.
Continue - Resetting the adaptation and oil quality counter
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Resetting the oil quality counter
Resetting the "Transmission fluid change" counter
Resetting the "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 incorrectly. Therefore it is important that the "Transmission oil change" counter is reset.
Note! This only applies when the transmission fluid is changed and when the fluid is changed during repairs to the transmission temperature sensor.
- Ignition on.
Click on the VCT2000 symbol to reset the counter.
Continue - DONE
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DONE - Verification
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Resetting the adaptation and oil 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 solenoids 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, components, etc.
- Ignition on
Test drive the vehicle following: Test drive schedule, description Test Drive Schedule, Description
During the test drive, oil temperature should be over 20 °C.
Note any deviations in transmission function.
Does the transmission function flawlessly?
Yes - VERIFIED
No - VERIFICATION FAILED
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VERIFICATION FAILED - Fault-tracing information
VERIFIED - FAULT FOUND
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Fault-tracing 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 - Exit fault-tracing
No - Attempt New Test
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Attempt New Test - Checking the oil quality and the oil level in the transmission
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