Mechatronic Unit, Transmission Installed
Mechatronic Unit, Transmission Installed
Special tools, testers and auxiliary items required
• Torque Wrench (5-50 Nm) (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 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.
The Mechatronic unit 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.
If necessary:
- Remove the charge air hose between the charge air cooler and charge air pipe.
• It is possible that parts, which have nothing to do with the Mechatronic unit, will have to be removed. It depends on the vehicle equipment. Make sure there is enough room around the Mechatronic unit.
• Depending on the vehicle, the parts could be:
• Fan shroud
• Additional lines for the Air Conditioning (A/C) system
• Charge or cold air pipes
- Remove the cable bracket from the large transmission cover (2 M6 nuts).
- Release the Mechatronic connector retainer by rotating and remove connector.
- Position the lines in the area of the cover upward and secure.
- Place the (V.A.G 1782) under the 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 behind the 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.
Approximately 5.0 liters of oil will drain out. The (V.A.G 1782) should remain under the transmission.
In regards to contaminated oil, also observe information on changing the oil filter.
- Reinstall the overflow tube, and tighten it to 3 Nm.
- Loosen the cover bolts - arrows - diagonally and remove them.
- Remove the cover and seal.
• Always replace the bolts for the cover.
• The seal on the cover must also be replaced.
In order to have enough free space to remove the Mechatronic, the pendulum support can be removed.
Then the transmission can be pressed down and back slightly.
Before handling the Mechatronic unit, touch a grounded object.
- 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. Replace the sensor if this happens.
Do not pull on the wire!
- Remove the connector.
- Remove the wire from the retaining 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 again.
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 the 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 under the upper, and then under the lower retaining tab - arrows -.
- Connect and engage the connector.
- Replace both O-rings, if the old Mechatronic unit is being reinstalled.
- Coat the O-rings with DSG oil.
(A new Mechatronic unit naturally already has new O-rings.)
- Clean the cover seal and transmission sealing surfaces.
- Ensure the correct seal seating.
- Place the cover over the Mechatronic unit without pinching any wires.
- Install the new bolts - arrows - and tighten them diagonally in multiple stages to 10 Nm.
- Install the cable bracket to the cover and then tighten the nuts to 10 Nm.
- Connect the connector for the Mechatronic unit and engage the retainer by turning.
- Install the charge air hose between the charge air cooler and charge air pipe, if necessary.
- Reinstall any vehicle parts removed.
- Connect the battery ground cable.
- Do not start the engine!
- Change the oil filter if the oil is dirty.
- Replace the DSG oil and filter.
- Install the noise insulation.
- Perform a basic measurement on the Mechatronic unit.