Hydraulic Control Unit: Installing

NOTE:

Always follow the safety precautions when replacing the hydraulic control unit. Install the "old" sensors again if possible. Refer to SAFETY PRECAUTIONS AND TEST PROCEDURES .

Conditions:

Replace the seal between the hydraulic control unit -1- and the final drive housing.

Fig 1: Identifying Hydraulic Control Unit
Courtesy of AUDI OF AMERICA, LLC
The centering pins -18- HYDRAULIC CONTROL UNIT => List Item:Hydraulic Control Unit Housing must be installed inside the hydraulic control unit.
The left -6- and right -7- pipes must installed loosely inside the control unit when attaching the hydraulic control unit -1- to the rear final drive.

Attach the hydraulic control unit -1- to the rear final drive as follows:

First install the pipes -6 and 7- into the chambers hand-tight -arrows B-.

Install the bolts -2 through 5- hand-tight. The bolt -2- has permanent seal on the bolt head. Coat the thread on this bolt with sealing compound D 176 501 A1.

Then tighten the bolts -2 through 5- to the tightening specification in the following sequence: -4-, -2-, -5- and -3- (M8 x 30 mm).

Tighten the nuts -arrows A- and -arrows B- on the left -6- and right -7- pipes to the tightening specification.

-- Install the AWD pump. Refer to PUMP .

-- Install the wiring harness -3- on the final drive and subframe -5 through 7-.

Fig 2: Identifying Rear Final Drive Wiring Harness Bracket

Courtesy of AUDI OF AMERICA, LLC

-- Connect the connectors -4 and 2- using the markings made earlier when oil pressure/temperature sensor -- and the clutch valve -- were removed.

-- If equipped, hold the wiring harness bracket -1- on the rear final drive and then tighten the bolts -arrows- to the tightening specification. Be careful not to pinch the wiring harness -3-.

NOTE:

Connector allocation for the oil pressure/temperature sensor -- and the clutch valves -- :

Fig 3: Oil Pressure/Temperature Sensor Connector

Courtesy of AUDI OF AMERICA, LLC

-1- = oil pressure/temperature sensor 2 -G640- connector

-2- = oil pressure/temperature sensor -G437- connector

-3- = AWD clutch valve 2 -N446- connector

-4- = AWD clutch valve -N445- connector

-- Fill the gear oil in the rear final drive and check the level. Refer to GEAR OIL LEVEL IN REAR FINAL DRIVE 0BF AND 0BE, CHECKING .

-- Fill the ATF in the rear final drive and check the level. Refer to ATF LEVEL IN REAR FINAL DRIVE 0BF AND 0BE, CHECKING .

-- Install and adjust rear section of exhaust system free of stress. Refer to OVERVIEW - MUFFLER (3.0L - CREC and CREA), OVERVIEW - MUFFLER (3.0L - CPNA), MUFFLER OVERVIEW (3.0L - CTUB), OVERVIEW - MUFFLER (4.0L - CEUA, CGTA, CTFA and CTGA) or OVERVIEW - MUFFLER (6.3L - CEJA and CTNA) .