VW Golf manuals

Volkswagen Golf Service & Repair Manual: Removing and installing mechatronic unit for dual clutch gearbox -J743

Special tools and workshop equipment required
Vehicle diagnostic tester
   
Used oil collection and extraction unit -V.A.G 1782-
 

Removing and installing mechatronic unit for dual clutch gearbox -J743

Engine bung set -VAS 6122-; alternatively sealing cap -0AM 325 120 A-
 

Removing and installing mechatronic unit for dual clutch gearbox -J743

Assembly lever -T10407-
 

Removing and installing mechatronic unit for dual clutch gearbox -J743

Guide pin -T10406-
 

Removing and installing mechatronic unit for dual clutch gearbox -J743

Diesel extractor -VAS 5226-
Requirement:
Gearbox is installed.
Brief description
In order to remove the mechatronic unit, sufficient space must be available in front of the gearbox. Depending on the vehicle, parts must be removed which do not have anything to do directly with the gearbox. For example: air filter housing, if present, charge air lines or coolant lines.
Fitted retainers may also have to be removed.
Tester moves all gear actuators »into neutral position«.
In this position, insert assembly lever -T10407- between clutch lever and gearbox housing.
Safety note on mechatronic unit for dual clutch gearbox -J743-
 

Removing and installing mechatronic unit for dual clutch gearbox -J743

Removing and installing mechatronic unit for dual clutch gearbox -J743
 

  DANGER!
Do not work on pressure accumulator. The accumulator is under pressure and is not allowed to be opened.
  Caution
Danger of irreparable damage to gearbox.
Do not run engine or tow vehicle with mechatronic unit for dual clutch gearbox -J743- removed or when there is no gear oil in the gearbox.
  Note
Observe → Chapter „Repair instructions“.
The clutch is self-adjusting. Shocks can have an effect on this adjusting device. Even if the mechatronic unit has been removed, suddenly pulling out the assembly lever -T10407- from under the engaging levers can have a negative effect on the adjusting mechanism.
A »new« mechatronic unit is correctly filled with oil. Do not drain or top up oil.
Recalibrate the immobiliser after installing a »new« mechatronic unit.
If a mechatronic unit is sent back, always observe the corresponding requirements.
Removing
–  Raise vehicle. All 4 supports of lifting platform must be at same height.
–  Move selector lever to position »P«.
  Note
The vehicle diagnostic tester moves all gear actuators into “neutral” position.
In this position, insert assembly lever -T10407- between engaging lever and gearbox housing. This allows for removing load from plungers of mechatronic unit so that they can be removed by hand from mountings of engaging levers.
–  Connect vehicle diagnostic tester and switch on ignition.
–  Select the following menu options:
Guided Functions
02 - 7-speed dual clutch gearbox
Basic setting neutral
–  Switch off ignition.
Vehicles with diesel engine:
Remove air filter housing → Rep. gr.23.
Continued for all vehicles:
–  Remove noise insulation → Rep. gr.66.
  Caution
Risk of damaging gearbox components beyond repair.
Do not under any circumstances touch the contacts in the gearbox connector by hand. Electrostatic discharge can seriously damage the control unit and mechatronic unit.
–  Touch earth connection (without gloves) in order to discharge yourself.
   
–  Disconnect electrical connector -1- for mechatronic unit for dual clutch gearbox -J743-. To do this, pull locking mechanism upwards -arrow-.
–  Unscrew nuts -2- and -3- and remove wiring retainer from gearbox.
–  Tie up wiring in area of gearbox cover.
 

Removing and installing mechatronic unit for dual clutch gearbox -J743

–  Put used oil collection and extraction unit -V.A.G 1782- underneath.
–  Unscrew oil drain plug of gearbox.
–  Allow oil to drain off, then screw in oil drain plug firmly again.
  Caution
It is not possible to check the fill level of the hydraulic fluid section of the mechatronic unit for dual clutch gearbox -J743-. For installation work, the breather of the mechatronic unit for dual clutch gearbox -J743- must be sealed so that no oil can escape → Anchor. If any oil escapes from the hydraulic fluid section of the mechatronic unit for dual clutch gearbox -J743-, it is not possible to replenish it or check the level!
 

Removing and installing mechatronic unit for dual clutch gearbox -J743

–  Pull cap -arrow- off breather connection on mechatronic unit. Seal connection using a clean plug from engine bung set -VAS 6122- so that no oil can escape.
  Note
The breather cap on the mechatronic unit is destroyed during removal and must be renewed.
The mechatronic unit can be sealed using sealing cap -0AM 325 120 A- as an alternative → Electronic Parts Catalogue (ETKA).
 

Removing and installing mechatronic unit for dual clutch gearbox -J743

–  If fitted, remove cover on engaging levers.
The cover prevents dirt getting in.
 

Removing and installing mechatronic unit for dual clutch gearbox -J743

–  Carefully pull gearbox input speed sender 3 -G641- out of gearbox -arrow-.
  Note
The following work step serves to lift off both engaging levers of the dual clutch from the plungers of the mechatronic unit. If this is not done, the engaging levers will jam the mechatronic unit at the plungers and prevent the mechatronic unit from being removed.
 

Removing and installing mechatronic unit for dual clutch gearbox -J743

–  Insert assembly lever -T10407- under plunger -2- between gearbox housing and both engaging levers -1--arrow-, as shown in illustration.
 

Removing and installing mechatronic unit for dual clutch gearbox -J743

–  Insert assembly lever -T10407- just enough until groove is flush with housing rib -arrows-, as shown in diagram. Do not insert onto stop.
  Note
The back of the assembly lever must rest against the gearbox housing when doing this.
 

Removing and installing mechatronic unit for dual clutch gearbox -J743

–  Apply a bit of force to tip of lever when turning.
This stops lever from slipping out when turning.
 

Removing and installing mechatronic unit for dual clutch gearbox -J743

Turn assembly lever -T10407- anticlockwise. In this way, engaging levers are pressed away from plungers.
 

Removing and installing mechatronic unit for dual clutch gearbox -J743

Do not take out assembly lever -T10407-. The assembly lever remains inserted between clutch lever and gearbox housing for the entire process.
–  If necessary, press assembly lever -T10407- against gearbox using a screwdriver.

Removing and installing mechatronic unit for dual clutch gearbox -J743
 

  Note
The assembly lever -T10407- must remain inserted between clutch lever and gearbox housing after removing the mechatronics. Removing the lever could have a negative effect on the clutch adjustment.
  Caution
Risk of damaging mechatronic unit for dual clutch gearbox -J743-.
Do not loosen the bolts for cover of the mechatronic unit for dual clutch gearbox -J743-.
Place the removed mechatronic unit for dual clutch gearbox -J743- down in such a way that no oil can escape through the breather.
Oil which has been drained out cannot be filled again
   
–  Remove bolts -B- in diagonal sequence.
–  Unscrew bolts -A-, and remove mechatronic unit from gearbox.
–  Make sure no oil runs out of breather.
On some vehicles, a coolant hose prevents the mechatronic unit from being removed. In this case, reinsert mechatronic unit, and secure it against falling down with a bolt.
 

Removing and installing mechatronic unit for dual clutch gearbox -J743

–  Remove lower left coolant hose from radiator → Rep. gr.19.
Some additional space in front of the mechatronic unit can be obtained by removing the pendulum support from the gearbox. This allows the gearbox to be »pushed back« a little in order to remove the mechatronic unit.
 

Removing and installing mechatronic unit for dual clutch gearbox -J743

–  Remove bolts -1- securing pendulum support to gearbox.
–  Remove mechatronic unit, and place it in such a way that no oil can escape from the breather hole.
  Caution
Risk of damaging mechatronic unit for dual clutch gearbox -J743-.
Sometimes, the mechatronic unit cannot be removed.
In this case, the gear actuator is caught at the top left of the mechatronic unit.
The mechatronic unit must not be pulled out using excess force.
In this case, the mechatronic unit should first be brought into the installation position by hand → Chapter.
  Note
The remaining oil must be extracted from the gearbox before the mechatronic unit is fitted.
 

Removing and installing mechatronic unit for dual clutch gearbox -J743

–  All the oil remaining in the gearbox must be removed using diesel extractor -VAS 5226-.
Installing
Requirement:
 

Removing and installing mechatronic unit for dual clutch gearbox -J743

The assembly lever -T10407- is inserted between clutch lever and gearbox housing.
  Note
Observe the following when installing a new mechatronic unit:
After unpacking a new mechatronic unit, do not discard the packaging or the red cap on the breather pipe. These will be needed for returning the old mechatronic unit.
A »new« mechatronic unit is correctly filled with oil. Do not drain or top up oil.
Recalibrate the immobiliser after installing a »new« mechatronic unit.
–  Before inserting mechatronic unit, check each of the 4 selector forks in gearbox by hand.
Each selector fork has 3 positions:
Gear engaged
Neutral position -N-
Gear engaged
–  Move each of the 4 selector forks one after the other into each position -arrows-. Slightly turn one wheel to ease the movement of the selector forks.
 

Removing and installing mechatronic unit for dual clutch gearbox -J743

Removing and installing mechatronic unit for dual clutch gearbox -J743

N -  Neutral position
R -  Reverse gear
1 -  First gear
2 -  Second gear
3 -  Third gear
4 -  Fourth gear
5 -  Fifth gear
6 -  Sixth gear
7 -  Seventh gear

 
–  Then move all selector forks back to »centre position« (position -N-).
–  Clean sealing surface where mechatronic unit will make contact later on.
   
–  Screw in guide bolts -T10406- by hand.
Make sure that the gear actuators are adjusted correctly:
 

Removing and installing mechatronic unit for dual clutch gearbox -J743

Removing and installing mechatronic unit for dual clutch gearbox -J743

  Caution
Risk of damaging mechatronic unit for dual clutch gearbox -J743-.
When levering out the plungers, do not use the sensors as an anchor point.
–  Move the 4 gear actuators of the mechatronic unit for dual clutch gearbox -J743- to the specified position.
Specified position: -a- = 25 mm.

 
     
–  Clean sealing surface of mechatronic unit.
The seal around mechatronic unit for dual clutch gearbox -J743- must be fully and properly inserted in the groove.
 

Removing and installing mechatronic unit for dual clutch gearbox -J743

–  Put on mechatronic unit.
–  Insert and tighten new bolts for mechatronic unit. Specified torques: → Fig.
  Caution
Risk of damaging clutches.
If the engaging levers strike the clutch actuators of the mechatronic unit hard, these will be placed under excess pressure and the self-adjusting device of the clutch will become active. Self-adjustment cannot be reversed.
Both clutch actuators must be engaged correctly in retainers of clutch engaging levers -arrow-.
Do not damage rubber grommets of clutch actuators when doing this.
Rubber grommets must seal properly against mechatronic unit.
 

Removing and installing mechatronic unit for dual clutch gearbox -J743

–  Carefully and slowly turn assembly lever -T10407- in clockwise direction and remove it.
The plungers must slide slowly into the mountings.
–  Pull out plungers by hand until they are properly seated in mountings.
 

Removing and installing mechatronic unit for dual clutch gearbox -J743

–  Pull sealing plug off breather connection on mechatronic unit and fit new breather cap -arrow-.
 

Removing and installing mechatronic unit for dual clutch gearbox -J743

–  If present, install cover on engaging levers. Specified torques → Chapter
 

Removing and installing mechatronic unit for dual clutch gearbox -J743

–  Install new bolts -1- securing pendulum support to gearbox, if they have been removed before → Rep. gr.40.
Further installation is carried out in the reverse order of removal; note the following:
–  Fill with gear oil → Chapter.
–  Check selector lever cable adjustment and adjust it if necessary → Chapter.
–  Install noise insulation → Rep. gr.66.
–  After installation, perform a Complete reset by means of Guided functions → Vehicle diagnostic tester.
 

Removing and installing mechatronic unit for dual clutch gearbox -J743

Exploded view - mechatronic unit
1 -  Bolt For securing mechatronic unit for dual clutch gearbox -J743- on gearbox housing. Qty 3, M8 x 35 Always renew ...

Moving mechatronic unit for dual clutch gearbox -J743- into removal position by hand
  Note Only if you cannot set the mechatronic unit to removal position with the vehicle diagnostic tester, you must set the unit by hand to removal position. ...

Other materials:

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