Hydraulic Control Unit, Disassembling And Assembling

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Fig 1: Exploded View Of Hydraulic Control Unit

Courtesy of AUDI OF AMERICA, LLC

Bolt
- 5 Nm
All Wheel Drive Pump -V415-
- Removing and installing. Refer to All Wheel Drive Pump -V415-, REMOVING AND INSTALLING .
O-Ring
- Always replace.
Adapter
NOTE:
The adapter could fall out when removing the All Wheel Drive Pump -V415-.

Insert the adapter into the recesses in the hydraulic pump before installing the All Wheel Drive Pump -V415-.
Hydraulic Pump
- Consists of a guide ring, the housing and six pistons
- Assembling. Refer to Fig 2
Ball Bearing
- Can be installed and removed by hand
Left Line
- Tighten the nuts to 30 Nm.
- Is installed between the hydraulic control unit and the left chamber
- Tighten both nuts hand-tight when installing
O-Ring
- Always replace.
Oil Pressure/Temperature Sensor -G437-
- 10 Nm
- Brown connector
- Removing and installing. Refer to Oil Pressure/Temperature Sensor -G437- OR Oil Pressure/Temperature Sensor 2 -G640-, REMOVING AND INSTALLING .
Oil Pressure/Temperature Sensor 2 -G640-
- 10 Nm
- Black connector
- Removing and installing. Refer to Oil Pressure/Temperature Sensor -G437- OR Oil Pressure/Temperature Sensor 2 -G640-, REMOVING AND INSTALLING .
All Wheel Drive Clutch Valve 2 -N446-
- Color: brown
- Removing and installing. Refer to All Wheel Drive Clutch Valve -N445- OR All Wheel Drive Clutch Valve 2 -N446-, REMOVING AND INSTALLING .
- Installed position, the connector faces upward toward the Oil Pressure/Temperature Sensor --
  CAUTION:
  Do not interchange with the All Wheel Drive Clutch Valve -N445-.
All Wheel Drive Clutch Valve -N445-
- Color: black
- Removing and installing. Refer to All Wheel Drive Clutch Valve -N445- OR All Wheel Drive Clutch Valve 2 -N446-, REMOVING AND INSTALLING .
- Installed position, the connector faces upward toward the Oil Pressure/Temperature Sensor --
  CAUTION:
  Do not interchange with the All Wheel Drive Clutch Valve 2 -N446-.
Bolt
- 2.5 Nm
O-Ring
- Always replace.
- Mount onto the Clutch Valve --
Pressure Spring
- Insert into the guide. Refer to -item 16- below (See Fig 1).
Guide
- Installation position, large diameter faced the ball. Refer to -item 17- below.
Ball
- Insert into the guide before installing. Refer to -item 16- above.
Hydraulic Control Unit Housing
- With centering pins -arrows-
- The centering pins lock the hydraulic control unit and seal to the final drive housing.
Ball
- Install in the hole in the shuttle valve before installing, Refer to -item 21- below.
O-Ring
- Always replace.
Shuttle Valve
- 8 Nm
- Removing and installing. Refer to Fig 4.
Gasket
- With strainer
- Install on the centering pins in the hydraulic control unit housing
Right Line
- Tighten the nuts to 30 Nm.
- Is installed between the hydraulic control unit and the right chamber
- Tighten both nuts hand-tight when installing

Fig 2: Assembling Hydraulic Pump

Courtesy of AUDI OF AMERICA, LLC

-- Install the six pistons -A- in the housing -B-.

-- Install the guiding ring -C- so that the piston touches the collar -arrow-.

-- Insert the hydraulic pump -1- with the guide ring -2- in the in the hydraulic control unit housing.

Fig 3: Hydraulic Control Unit Housing

Courtesy of AUDI OF AMERICA, LLC

Function Test

-- Turn the hydraulic pump -1- several times. While doing so pay attention to the following:

When turning the hydraulic pump must not become hooked or tilted.
All pistons must be removed and pressed in.

Fig 4: Removing/Installing Shuttle Valves

Courtesy of AUDI OF AMERICA, LLC

NOTE:

Remove the All Wheel Drive Pump -V415-, hydraulic pump and ball bearing beforehand. Refer to -item 6- Ball Bearing (See Fig 1).

-- Remove the shuttle valves -A-. Always remove the ball -C- as well.

-- Insert the ball into the hole in the shuttle valve when installing.

-- Install the shuttle valve all the way with a new O-ring -B-.

The shuttle valve must rest lower than the opposing housing surface -arrow-. If this is not the case, then remove the valve again and adjust the position of the ball.

-- Tighten the shuttle valve to the tightening specification. Refer to -item 21- Shuttle Valve (See Fig 1).