Mechatronic Unit, Transmission Installed
Mechatronic Unit, Transmission Installed
Special tools, testers and auxiliary items required
• Torque Wrench (V.A.G 1331)
• Oil Collecting and Extracting Device (V.A.G 1782 )
Removing
Always make sure that no dirt enters an open transmission.
Dirt entering on open transmission can cause a malfunction especially with the Direct Shift Gearbox (DGS) Mechatronic (J743) and/or oil pump.
In regards to contaminated oil, also observe information on changing the oil filter. Refer to => [ When To Change Oil Filter ] General Repair Information.
The Mechatronic can get stuck on the alignment pins when the transmission is very warm. Let the transmission cold down.
- Place the selector lever in the "P" position.
- Disconnect the battery ground (GND) cable with the ignition turned off.
- Remove the noise insulation.
- Remove the connecting hose between the charge air cooler and charge air pipe, if necessary. Refer to one of the following:
Gas engines.
Diesel engines.
• It is possible that parts, which have nothing to do with the Mechatronic unit, will have to be removed depending on vehicle equipment. Make sure there is enough room around the Mechatronic unit.
• Depending on the vehicle, the components could be:
• Radiator fan shroud
• Additional lines for the Air Conditioning (A/C) system
• Charge or cold air pipes
- Remove the cable bracket from the large front transmission cover (2 M6 nuts).
- Release the Mechatronic connector retainer by rotating and remove the connector.
- Position the wires in the cover area upward and secure them.
- Place (V.A.G 1782) under transmission.
- 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 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.
Approximately 5.0 liters of oil will flow out. The (V.A.G 1782) should remain under the transmission.
In regard to contaminated oil, also observe information on changing the oil filter. Refer to => [ When To Change Oil Filter ] General Repair Information.
- Reinstall the overflow tube and tighten it to 3 Nm.
- Remove the bolts - arrows - (diagonally) for the large front cover.
- Remove the front cover and seal.
• Always replace the bolts for the cover.
• The seal for the cover must also be replaced.
In order to have enough free space to remove the Mechatronic unit, the pendulum support can also be removed.
Then the transmission can be pressed down and back slightly.
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 mechanism can break. Replace the sensor if this happens.
Do not pull on the wire!
- Remove the connector.
- Remove the wire from the tabs - arrows -.
- Loosen and remove the bolts - 1 through 10 - in the specified sequence.
• It is not necessary to remove the side cover in order to install or remove the Mechatronic unit.
• The side cover is not shown in the illustration.
- Carefully pull the Mechatronic unit out of the transmission housing far enough until the sensor arm - B - on the rear side is no longer located in the transmission housing.
When handling the Mechatronic unit, be particularly aware of the long sensor arm.
- Carefully swivel the Mechatronic unit downward.
- Store the Mechatronic unit properly.
Storing the Mechatronic Unit Properly
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.
Installing
Before handling the Mechatronic unit, touch a grounded object, refer to => [ Electrical Components ] General Repair Information.
If the sensor arm is damaged, the Mechatronic unit must be replaced.
- Carefully insert the Mechatronic unit into the transmission housing.
• The side cover was not removed.
• The side cover is not shown in the illustration. This shows why the long arm can get damaged if the Mechatronic unit is tilted.
The Mechatronic unit and transmission must be the same temperature. The alignment pins will not clamp during installation.
- Do not pinch the wire.
Make sure the wire does not get pinched.
- Carefully place the Mechatronic unit on the alignment pin - arrow -. Make sure the sensor arm is in the installed position.
- Hold the Mechatronic unit facing up. The sensor arm must not touch the sensor wheel.
- Make sure the Mechatronic unit is installed correctly.
- Install the new bolts - 1 through 10 - hand tight.
- Tighten the bolts in the specified sequence to 5 Nm + 90° (1/4) additional turn.
- Hook the wire - A - first into the upper tab and then into the lower tab - arrows -.
- Connect the connector.
- Replace both O-rings - arrows -, if the old Mechatronic unit is being reinstalled.
- Lubricate the O-rings - arrows - with DSG oil.
(A new Mechatronic naturally already has new O-rings.)
- Clean the cover seal and transmission sealing surfaces.
- Ensure the correct seal seating.
- Place the large cover over the Mechatronic without pinching any wires.
- Install new bolts - arrows - and tighten diagonally in multiple stages to 10 Nm.
- Install the cable bracket to the large cover and then tighten the nuts to 10 Nm.
- Connect the connector of the Mechatronic unit and engage the retainer by turning.
- Install the charge air hose between the charge air cooler and charge air tube, if necessary. Refer to one of the following:
Gas engines.
Diesel engines.
- Reinstall any vehicle parts that were removed.
- Connect the battery ground (GND) cable.
- Do not start the engine!
- Change the filter if the oil is dirty.
- Replace the DSG oil and filter. Refer to => [ Oil Filter and Oil Level, Changing and Adjusting ] Testing and Inspection.
- Install the noise insulation.
- Perform a basic measurement on the Mechatronic unit.