1999 AUDI A8 transmission

39-45


Center differential, servicing Transmission installed
Special tools and equipment

VW401 thrust plate
VW412 punch
VW402 thrust plate
VW454 thrust tube
VW407 punch
3021 protractor
Pa
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39-46


WARNING!
Do not run engine with the center differential
removed or without gear oil and do not tow
vehicle.
Notes:
The parts listed in the following illustration can be
removed with the transmission installed.
4020 press tube
3118 press support
Item 3 Kukko 17/2 separating tool
Rules of cleanliness for working on automatic
transmissions page 37
-148
.
General repair notes page 00
-27
.
Pa
ge 2 of 29 Center differential, servicin
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39-47


1 -
Socket head bolt - 25 Nm
2 -
Rear drive flange
3 -
Seal
Always replace page 39
-61
4 -
Bolt - 23 Nm
4x
5 -
Housing cover
6 -
O-ring Coat with transmission fluid
7 -
Snap ring
8 -
Grooved ball bearing For spur gear 1Pressing off Fig. 1
, page 39
-54
Pressing on Fig. 2
, page 39
-54Pa
ge 3 of 29 Center differential, servicin
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39-57


- Unbolt driveshaft -1- from transmission and let rest on heat shield -2-
page 39
-79
, Driveshaft, removing and installing.
- Secure driveshaft using wire (arrow) at bracket -3- of fuel lines.
- Drain center differential gear oil page 39
-40
.

WARNING!
Carefully pull center differential housing off of transmission toward
rear. The Torsen differential could otherwise fall out of the
transmission. - Loosen mounting bolts (arrows) for center differential housing in
diagonal sequence and remove.
Pa
ge 13 of 29 Center differential, servicin
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39-59

- Add 200 ml. gear oil to output housing
(comparable to gear oil, topping up on removed
and disassembled center differential page 39
-
43
).

- Install Torsen differential onto splines of output shaft and bottom spur
gear while turning slowly.
- Check whether installed Torsen differential can be turned by hand.

- Install fully assembled transfer housing with installed spur gears and
rear drive flange onto transmission flange.
- Insert bolts for transfer housing and tighten to final tightening torque in
diagonal sequence in several stages.
- Bolt driveshaft to transmission flange page 39
-79
, Driveshaft,
removing and installing.
- Fill transfer housing with gear oil and check oil level page 39
-40
.
Pa
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39-60

Tightening torques

Component
Nm
Center differential housing to transmission
housing 23
Heat shield for driveshaft to transmission 23
Pa
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39-62


- Unbolt driveshaft -1- from transmission and let rest on heat shield -2-
page 39
-79
, Driveshaft, removing and installing.
- Secure driveshaft using wire (arrow) at bracket -3- of fuel lines.
- Drain center differential gear oil page 39
-40
.

- Unbolt output flange while securing output flange against turning using
a drift.
- Pull out output flange.
Pa
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39-64

Installing
Installation is reverse of removal, noting the
following:

Tightening torques - Drive O-ring in to stop using 3402 pressure piece.
- Secure output flange with socket-head bolt.
- Bolt driveshaft to transmission flange page 39
-79
, Driveshaft,
removing and installing.
- Fill transfer housing with gear oil and check oil level page 39
-40
.
Component
Nm
Socket-head bolt for rear drive flange 25
Heat shield for driveshaft to transmission 23
Pa
ge 20 of 29 Center differential, servicin
g
11/20/2002 htt
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yp
e=re
pair&id=AUDI.B5.AT01.39.4