AUDI A4 1996 B5 / 1.G 01A Transmission Total Shim Thickness Owner's Manual

Torque gauge 0-600 Ncm (53 in. lb)
Dial indicator
Dial indicator extension
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39-58

Determining total shim thickness "Stotal" (S1
+ S2)
Adjusting preload of tapered roller bearings for
differential

Pinion shaft removed

Note:
If only the tapered roller bearings for the
differential are being replaced, the ring gear can
be removed from the differential housing. The
pinion shaft does not have to be removed.

- Remove seals and outer races of both tapered
roller bearings for differential.

- Remove shims Page 39
-21
.

Note:
For measurement purposes, a shim S2 of 1.20 mm is initially inserted and
referred to as S2* in the following text. After determining backlash, S2* will
be replaced by the correct shim S2. - Press right tapered roller bearing outer race with shim S2 into
transmission housing Fig. 2, Page 39
-27
. Shim S2* with thickness
of 1.20 mm (two 0.60 mm shims) is used for initial measurement.
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- Press tapered roller bearing outer race into differential cover without
shim S1 Fig. 8, Page 39
-31
.
- Insert differential without speedometer gear drive into transmission
housing. Ring gear is positioned on left-hand side infront of final drive
cover.
- Install differential cover with 4 bolts and tighten to 25 Nm (18 ft lb).
- Position transmission so differential cover faces upward.
- Turn differential 5 turns in both directions so tapered roller bearings
settle.

Note:
The tip of the dial indicator must be positioned on the center of the
differential. - Assemble measuring equipment, using 30 mm dial indicator extension.
- Set dial indicator (3 mm measuring range) -A- to "0" with 2 mm
preload.
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39-60

- Lift differential without turning, and read off play
on dial indicator.

Measurement in following example: 0.62 mm

Notes:

To lift the differential, attach VW521/4 locking sleeve and VW521/12
on the right of the differential (housing side). If the measurement has to be repeated, the pinion shaft with hollow
shaft must be turned 5 turns in each direction first to settle the tapered
roller bearing.
Formula:
Stotal
=
S2*- + measurement + bearing preload
Example

Inserted shim(s) S2* 1.20 mm
+ Measured value 0.62 mm
+ Bearing preload (constant value) 0.30 mm
= Total thickness Stotal for S1 + S2 2.12 mm
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39-61

Determining thickness of shim "S1*"

Notes:

The preliminary adjustment shim S1* will be
replaced with the final shim S1 after
determining the backlash.
The total shim thickness Stotal remains
unchanged.

Formula:
S1* = Stotal - S2*



Example:


Total thickness Stotal for S1 +
S2
2.12
mm
- Inserted shim(s) S2* 1.20
mm
= Thickness of shim S1* 0.92
mm
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39-62

Measuring friction torque

Notes:

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 Stotal.
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.
Pinion shaft removed

Friction torque specifications:
Note: - Install torque gauge 0-600 Ncm (53 in. lb) -A- onto differential.
B - Socket
- Read friction torque.
New bearings
Used bearings
150-350 Ncm (13-31 in. lb) 30-60 Ncm (3-5 in. lb)
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For a readjustment of the final drive gear set (pinion shaft and ring gear),
the pinion shaft adjustment should now be checked Page 39
-39
.
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39-63

Measuring backlash
Position of ring gear in transmission housing

Pinion shaft with shims S3* and S4* installed

- Install differential.

- Turn differential 5 turns in each direction to
settle tapered roller bearings.

- Secure VW387 dial indicator holder onto housing.
- Attach VW521/4 locking sleeve and VW521/12.
- Install dial indicator and VW382/10 extension pin (6 mm flat).
- Adjust VW388 measuring lever to dimension -a-:
Distance -a-: 67 mm (2.637 in.) for 170 mm (6.693 in.) diameter ring
gear.
- Determine play between teeth flanks as follows:
- Turn ring gear until it makes contact with tooth flank (end of backlash
travel).
- Set dial indicator to "0" with 2 mm preload.
- Turn ring gear back against opposite tooth flank (backlash).
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39-64

- Recording (backlash) indicated on gauge.

-
Turn ring gear 90 further each time and
repeat measurement 3 times.
Notes:

Determining average backlash
CAUTION!
If the individual measurements differ by more than 0.06 mm from
each other, the installation of the ring gear or the final drive gear set
Install VW386A clamping piece if the pinion shaft rotates when the
differential is turned. This way the exact backlash can be measured. Loosen clamping piece in order to turn the ring gear further.
- Add four measured values together and divide by four.
Example:

1st measurement 0.28 mm
+ 2nd measurement 0.30 mm
+ 3rd measurement 0.30 mm
+ 4th measurement 0.28 mm
= Sum of measured values 1.16 mm Result: the average backlash is 1.16 mm 4 = 0.29 mm
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itself is not correct. Check installation, replace final drive gear set if
necessary.
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