2000 AUDI A6 differential

39-149

Readjusting final drive set,
recommended sequence

The following work sequence is recommended to
save time when the drive pinion and ring gear
have to be adjusted:

1.) Determine total shim thickness "S
total
" for
"S1" + "S2" for the specified preload for
tapered roller bearings for differential.
2.) Determine total shim thickness "S3" to
reproduce the installation position for the
drive pinion determined on the test machine
in production.
3.) Distribute total shim thickness "S
total
" for "S1"
+ "S2" so that the specified backlash exists
between ring gear and drive pinion.

Note:
Overview of components and shims Page 39
-
151
.
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39-150
Adjustment overview

Note:
If repairs have been carried out on the final drive it is only necessary to adjust the drive pinion or final drive set if components
have been replaced which have a direct effect on the adjustments of the final drive. Refer to the following table to avoid
unnecessary adjustments:

adjustment required:

Part replaced:

Ring gear
"S1"+"S2"
1)

Page 39
-163

Drive pinion
"S3"
1)
via deviation "r"
Page 39-154

Check backlash


Page 39
-169

Final drive housing X X X
Differential housing X X
Tapered roller bearing for drive pinion X X
Tapered roller bearing for differential X X
Final drive set
2)
X X X
Cover for final drive X X
1) Shims; installation position Page 39
-151
.
2) Drive pinion and ring gear; only replace together.
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39-163

Ring gear, adjusting

(Adjusting differential)
Repairs after which the ring gear has to be
adjusted Page 39
-150
, Adjustment overview

Note:

Differential tapered roller bearings are low
friction bearings. Therefore the friction torque
only has a limited use as a check. Correct
adjustment is only possible by determining the
total shim thickness "S
total
."

Do not additionally oil new tapered roller
bearings for friction torque measurement. The
bearings have already been treated with a
special oil by the manufacturer.

Determining total shim thickness "S
total
" for
shims "S1" + "S2"
(Setting preload of tapered roller bearing for
differential)

Drive pinion removed or ring gear dismantled
from differential housing

- Pull out drive flange oil seal with lever.
Pa
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- Remove differential tapered roller bearing outer
races and take out shims Page 39
-120
.
Pa
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39-164
Press outer race of left tapered roller bearing for
differential (housing side) with shim "S2" into
housing
Fig. 2 , Page 39
-126
. To perform
measurement use a shim "S2*" with a thickness
of 1.00 mm (one 0.80 mm shim and one 0.20
mm shim).

Note:
For measurement purposes a shim "S2" of 1.0
mm is initially inserted which will be designated
"S2*" in the following. After determining the
backlash "S2*" will be replaced by the correct
"S2.."

- Press in
outer race
of right
tapered
roller
bearing
for
differential
(final drive
cover
side)
without
shims
Fig. 8 , Page 39
-
120
(install as far as
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the stop).

- Insert differential into housing. Ring gear is
positioned on right side (cover side).

- Fit cover and tighten bolts to 25 Nm.

- Install special tools VW 521/4 and 521/8 onto housing side in
differential housing.
- Turn cover side of differential housing upward.
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39-165

- Turn differential 5 turns in both directions to
settle tapered roller bearing.

- Place measuring plate VW 385/17 onto
differential.

- Fit measuring tools.
A - Dial gauge extension approx. 30 mm long
B - Hex bolt M8 x 45
- Place D.T.I. extension on center of measuring plate VW 385/17.
- Set dial gauge (3 mm measuring range) to "0" with 2 mm preload.

Note:
If the measurement has to be repeated, the differential must again be
turned 5 turns in each direction to settle the tapered roller bearing. - Lift differential without turning; read play on dial gauge and note.
Measurement in following example: 0.50 mm
Pa
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39-168

Measuring friction torque (check)

Drive pinion removed
Differential fitted with shims "S1*" and "S2*"

Friction torque specifications: 1) run at least 50 km (30 miles)
Note: - Fit torque gauge 0-600 Ncm -A- onto differential.
- Read friction torque.New bearings
Used bearings
1)
150-300 Ncm 30-60 Ncm
Differential tapered roller bearings are low friction bearings. Therefore
the friction torque only has a limited use as a check. Correct
adjustment is only possible by determining the total shim thickness
"S
total
."
Do not additionally oil new tapered roller bearings for friction torque
measurement. The bearings have already been treated with a special
oil by the manufacturer. If the final drive set (drive pinion and ring gear) is being re-adjusted,
the adjustment of the drive pinion should be performed now, and the
Pa
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pinion and rin
g gear, ad
justin
g
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