Mechatronic Unit, Transmission Removed
Mechatronic Unit, Transmission Removed
Always make sure that no dirt enters an open transmission. Dirt entering an open transmission can cause a malfunction especially with the Direct Shift Gearbox (DSG) Mechatronic (J743) and/or oil pump.
In regard to contaminated oil, also observe information on changing the oil filter. Refer to => [ When To Change Oil Filter ] General Repair Information.
Removing
- Remove the inspection plug - A - near the pendulum support.
Up to transmission production date "September 20, 2004", transmissions with two plugs were installed.
A plastic overflow tube is located in this hole (with 8 mm hex socket head, tightening specification: 3 Nm). Its length determines the oil level in the transmission.
- Remove the overflow tube.
- Drain the oil.
In regard to contaminated oil, also observe information on changing the oil filter. Refer to => [ When To Change Oil Filter ] General Repair Information.
- Install and tighten the overflow tube to 3 Nm.
- If it is necessary, remove the filter.
There are often uncertainties as to whether the filter must be replaced or not.
For information on changing the oil filter, refer to => [ When To Change Oil Filter ] General Repair Information.
- Install the new filter with the seat facing downward and tighten the housing to 20 Nm.
- After performing repairs, the filter does not need to be changed again when filling with oil.
- Remove both the large Mechatronic cover and the small oil pump cover.
The oil pump cover and Mechatronic cover bolts must always be replaced.
The large cover seal must also be replaced.
Before handling the Mechatronic unit, touch a grounded object. Refer to => [ Electrical Components ] General Repair Information.
- Carefully unlock the transmission input speed RPM sensor (G182) and clutch oil temperature sensor (G509) connector using a small screwdriver - 1 -.
- Only push on the locking mechanism with the screwdriver - 1 -
- Do not pry on it.
Do not use the screwdriver as a lever.
- Loosen the connector using another screwdriver - 2 -.
Be very careful. The connector locking mechanisms can break. If this happens, replace the sensor.
Do not pull on the wire!
- Remove the connector.
- First remove the wire from lower tab - arrow I -.
- Then remove the wire from the upper tab - arrow II - and lay it aside. Do not kink the wire.
- Remove the bolts diagonally. Beginning with bolt - 1 -.
All 10 bolts must be replaced.
- Remove the Mechatronic unit.
When handling the Mechatronic unit, be particularly aware of the long sensor arm.
CAUTION!
Never lift the Mechatronic unit by, or allow it to rest on, the sensor arm.
If the sensor arm is damaged, the Mechatronic unit must be replaced.
- Store the Mechatronic unit properly.
Storing the Mechatronic Unit Properly
Installing
CAUTION!
Never lift the Mechatronic unit by, or allow it to rest on, the sensor arm.
If the sensor arm is damaged, the Mechatronic unit must be replaced.
- Before installing, make sure that the transmission input speed (RPM) sensor and clutch oil temperature sensor is installed.
- Replace both O-rings - arrows - on the Mechatronic unit, if the old unit is being reinstalled.
(A new Mechatronic naturally already has new O-rings)
- Lubricate the O-rings - arrows - with DSG oil.
- Carefully place the Mechatronic unit on the alignment pin - arrow -. Make sure the sensor arm is in the installed position.
- Do not pinch the wire.
Be sure not to pinch the wire.
All 10 bolts must be replaced.
- First install all bolts by hand.
- Tighten all 10 bolts diagonally to 5 Nm. Then tighten them and additional 90° further following the same sequence. Begin with bolt - 1 -.
- Install the transmission input speed (RPM) sensor and clutch oil temperature sensor wire first under the upper tab - II -. Then under the lower tab - I -.
- Press the connector onto the Mechatronic unit.
The small oil pump cover and large Mechatronic cover bolts must always be replaced.
The seal for the large cover must also be replaced.
- Tighten the cover bolts diagonally to 10 Nm.
After installing the transmission
- Fill the oil without replacing filter. Refer to => [ Oil Filter and Oil Level, Changing and Adjusting ] Testing and Inspection.
- Perform a basic measurement on the Mechatronic unit.