Hydraulic Control Unit: Service and Repair

23 42 534 - Replacing complete hydraulic unit (GS7S47BG SMG)





Special tools required:
- 00 1 450
- 24 0 200
- 24 0 202





Important!
Before working on hydraulic system:

- Reduce pressure in hydraulic system by means of Service Functions in DIS Tester (Replacement and Repair)
- Disconnect hydraulic pump relay Service and Repair in electronics box
Do not reconnect relay for entire duration of repair work





Important!
After working on hydraulic system:

- Perform bleeding using DIS Tester, refer to Service Functions in DIS Tester (Replacement and Repair)





Necessary preliminary tasks:
- Remove transmission Removing and Installing Transmission (GS7S47BG SMG)

Important!
A green sealing cap acting as a bleed replacement is seated on the tank of the new hydraulic unit.

Detach green sealing cap.

Replace with supplied black sealing cap.





Mount special tool 24 0 200 on transmission.

24 0 202 spindle with thrust piece is not needed.

Important!
Before mounting on assembly stand 00 1 450, check retaining bridge for secure seating.





Release screw (2).

Tightening torque 23 41 26AZ External Gearshift Components.

Installation Note:
Use high-temperature-resistant cable ties (approx. 140°).

If necessary, clean internal thread of screw housing (2).

Insert screw (2) with Loctite 243.





Release screw (1).

Tightening torque 23 41 24AZ External Gearshift Components.

Installation Note:
If necessary, clean internal thread of housing.





Release screws (1).

Tightening torque 23 41 26AZ External Gearshift Components.

Installation Note:
If necessary, clean internal thread of housing.





Release screws.

Tightening torque 23 41 28AZ External Gearshift Components.

Installation Note:
Replace screws.





Lever actuator block out of housing with a suitable tool (plastic wedge).

Important!
- Do not lever between actuator block and housing.
Sealing faces can be damaged.
- Do not lever on valves (1).





Important!
Cover transmission with a clean, fluff-free cloth.

Do not allow any dirt or contaminants to get into the transmission.

Clean sealing surfaces.

Installation Note:
Adapter sleeves (1) must be replaced if they remain in the actuator block during removal.





Before assembly:

Important!
Align shift forks (1) in transmission in centre position.

Apply a thin coating of Loctite 5203 (2).





Important!
Align shift travel piston on actuator block in centre position.

Rounded area must point upwards.

When installing actuator block, do not press on valves.





Join screws uniformly.

Tightening torque 23 41 28AZ External Gearshift Components.

Retighten screws in clockwise direction.