Valve Body: Service and Repair

Direct Shift Gearbox (DSG) Mechatronic (J743)

Special tools, testers and auxiliary items required

• Assembly Pin (T40199)

Removing


Risk of transmission damage.

• Do not run engine or tow vehicle with oil pan removed or without transmission fluid.

• => [ Repair Information ] Repair Information.

• => [ Clean Working Conditions ] Clean Working Conditions.

- Remove the ATF pan. Refer to => [ Oil Pan ] Service and Repair.

- Remove the front section of the left front wheel housing liner.





• Depending on the version, different wheel housing liner may be installed.


Risk of destroying Mechatronic with static discharge.

• Do not touch contacts in connector with hands.

Risk of damaging electrical wire.

• Do not pull on electrical wire.

- To discharge static, touch vehicle ground with hand (without glove).

- Carefully release electrical connector for the transmission input speed sensor (G182) and clutch oil temperature sensor (G509) with a small screwdriver - arrow - and remove.





• If electrical wire is damaged, transmission input speed sensor and clutch oil temperature sensor must be replaced.

- Release electrical connection to transmission input speed sensor and clutch oil temperature sensor from the retaining tabs on the mechatronic, first remove the lower electrical line - arrow I -.





- Remove the upper electrical line - arrow II - and set to the side, do not bend the line.


Risk of damaging Mechatronic.

• After removing the bolts from the mechatronic, do not remove it.

- Remove the bolts in the following sequence: - 1 to 10 -.






Risk of damaging mechatronic.

• Without the (T40199), the long sensor arm of the mechatronic will be damaged during removal.







- Attach 3 threaded holes for the bolts of the mechatronic for each guide pin (T40199), as shown in the image.

• The illustration shows the installation position with the cover removed for the oil pump.

• The cover for the oil pump must not be removed for this work.

• The long sensor arm - B - of the DSG Mechatronic may not be damaged.





- Carefully remove DSG mechatronic from the (T40199).


Risk of damaging mechatronic.

• If handled carelessly, the tabs - arrow 2 - on the sensor arm can break off.

• Do not lift mechatronic by sensor arm or lay it on arm.

• If sensor arm is damaged, the mechatronic must be replaced.

Installation

Install in reverse order, paying attention to the following:

Tightening specifications:

• => [ Oil Pan, Mechatronic and Transmission Fluid Pump Overview ] Oil Pan, Mechatronic and Transmission Fluid Pump Overview.

• DSG Mechatronic - tightening specification and sequence => [ - Tightening Specification and
Sequence ] Oil Pan, Mechatronic and Transmission Fluid Pump Overview.

• Replace O-rings - arrows - on DSG mechatronic connector.





• If DSG mechatronic is replaced, O-rings are contained in replacement part delivery package.

- Carefully insert DSG mechatronic in transmission housing through the (T40199).





• The illustration shows the installation position with the cover removed for the oil pump.

• The cover for the oil pump must not be removed for this work.

• The long sensor arm - B - of the DSG mechatronic may not be damaged.





- Make sure the alignment pin - A - in the transmission housing - arrow 1 - and the sensor arm - B - in the guide - arrow 2 - fit correctly on the transmission housing.

- Carefully position the mechatronic on the alignment pins and make sure the sensor arm moves into its installed position.

• Electrical wire to transmission input speed sensor and clutch oil temperature sensor must not be pinched.

- Tighten the DSG mechatronic bolts => [ - Tightening Specification and
Sequence ] Oil Pan, Mechatronic and Transmission Fluid Pump Overview.





- First hang the electrical line for transmission input speed sensor and clutch oil temperature sensor above - arrow II - and then under - arrow I -.





- Install the oil pan. Refer to => [ Oil Pan ] Service and Repair.

- If the old transmission fluid is dirty, replace it. Refer to => [ Transmission Fluid Filter ] Transmission Fluid Filter.

- Be sure to follow the procedure for connecting the battery and afterwards.

- Fill the transmission fluid. Refer to => [ Transmission Oil, Draining, Changing and Filling ] Transmission Oil, Draining, Changing and Filling.

- Start engine and run at idle.

- Press brake and shift through all selector lever positions "P, R, N, D, S" at idle, retaining each position for at least 3 seconds.

- Move the selector lever into "P".

- => [ Transmission Fluid, Checking and Filling ] Transmission Fluid, Checking and Filling.

- Basic Setting execute, using vehicle tester.