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 a open Direct Shift Gearbox (DSG) Mechatronic unit (J743) and/or oil pump.
In regards to contaminated oil, also observe information on changing the oil filter.
Removing
- Remove the 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 behind this plug (with a 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 regards to contaminated oil, also observe information on changing the oil filter.
- Reinstall and tighten the overflow tube to 3 Nm.
- If it is necessary, remove the oil filter.
There are often uncertainties as to whether the filter must be replaced or not.
- Insert 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 covers.
The small oil pump cover and large Mechatronic unit cover bolts must always be replaced.
The large cover seal must also be replaced.
Before handling the Mechatronic unit, touch a grounded object. R
- 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 wire!
- Remove the connector.
- First remove the wire from under the lower tab - arrow I -.
- Than remove from the wire from under the second tab - arrow II - and lay 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 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 on the Mechatronic unit connection if the old Mechatronic unit is being reinstalled.
(A new Mechatronic naturally already has new O-rings)
- Coat the O-rings 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 an additional 90° (1/4) turn following the same sequence. Beginning with bolt - 1 -.
- Install transmission input speed (RPM) sensor and clutch oil temperature sensor wire first under tab - II -. Then under tab - I -.
- Press the connector onto the Mechatronic unit.
The small oil pump cover and large Mechatronic unit 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.
- Perform a basic measurement on the Mechatronic unit.