Hydraulic Control Unit

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Fig 1: Hydraulic Control Unit Replacement Components

Courtesy of AUDI OF AMERICA, LLC

Bolt
- 5 Nm
All Wheel Drive (AWD) Pump -V415-
- Removing and installing, refer to PUMP
O-ring
- Always replace if removed
Adapter
NOTE:
The adapter could fall out when removing the AWD pump.

Insert the adapter into the recesses in the hydraulic pump before installing the AWD pump.
Hydraulic Pump
- Consists of a guide ring, a housing and 6 pistons
- Assembling, refer to Fig 2
Ball Bearing
- Can be removed and installed by hand
Left Pipe
- Tighten the nuts to 30 Nm.
- Installed between the hydraulic control unit and the left chamber
- First install the nuts hand-tight
O-ring
- Always replace if removed
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-
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-
All Wheel Drive (AWD) Clutch Valve 2 -N446-
- Color: brown
- Removing and installing, refer to CLUTCH VALVE OR CLUTCH VALVE 2
- Installation position: The connector faces upward toward the oil pressure/temperature sensor --
  CAUTION:
  Do not confuse with the AWD clutch valve.
All Wheel Drive (AWD) Clutch Valve -N445-
- Color: black
- Removing and installing, refer to CLUTCH VALVE OR CLUTCH VALVE 2
- Installation position: The connector faces upward toward the oil pressure/temperature sensor --
  CAUTION:
  Do not confuse with the AWD clutch valve 2.
Bolt
- 2.5 Nm
O-ring
- Always replace if removed
- Position on the clutch valve --
Compression Spring
- Install in the guide -item 16- HYDRAULIC CONTROL UNIT => List Item:Guide
Guide
- Installation position: The larger diameter faces the ball -item 17- HYDRAULIC CONTROL UNIT => List Item:Ball
Ball
- Insert into the guide before installing -item 16- HYDRAULIC CONTROL UNIT => List Item:Guide
Hydraulic Control Unit Housing
- With centering pins -arrows-
- The centering pins hold the hydraulic control unit and seal to the final drive housing.
Ball
- Insert into the hole in the shuttle valve -item 21- HYDRAULIC CONTROL UNIT => List Item:Shuttle Valve before installing
O-ring
- Always replace if removed
Shuttle Valve
- 8 Nm
- Removing and installing, refer to Fig 4
Gasket
- With a screen
- Mount on the centering pins on the hydraulic control unit housing
Right Pipe
- Tighten the nuts to 30 Nm.
- Installed between the hydraulic control unit and the right chamber
- First install the nuts hand-tight

Fig 2: Assembling Hydraulic Pump

Courtesy of AUDI OF AMERICA, LLC

-- Insert the 6 pistons -A- into the housing -B-.

-- Position the guide ring -C- so that the piston touches the collar -arrow-.

-- Install the hydraulic pump -1- and the guide ring -2- into the hydraulic control unit housing.

Fig 3: Hydraulic Control Unit Housing

Courtesy of AUDI OF AMERICA, LLC

Functional Check

-- Turn the hydraulic pump -1- several times. Pay attention to the following when doing this:

The hydraulic pump must not get stuck or tilt when being turned.
All the pistons must be pulled out and pushed in.

Fig 4: Identifying Shuttle Valves, Removal/Installation

Courtesy of AUDI OF AMERICA, LLC

NOTE:

Remove the AWD pump, the hydraulic pump and the ball bearing beforehand -item 6- HYDRAULIC CONTROL UNIT => List Item:Ball Bearing.

-- Remove the shuttle valves -A-. The ball -C- must be removed as well.

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

-- Carefully install the shuttle valve with a new O-ring -B- all the way in.

The shuttle valve must be deeper than the housing surface -arrow-. If this does not happen, then remove the valve again and adjust the position of the ball.

-- Tighten the shuttle valve to the tightening specification -item 21- HYDRAULIC CONTROL UNIT => List Item:Shuttle Valve.