differential AUDI A4 1998 B5 / 1.G 01A Transmission Final Drive Gear Set Workshop Manual

39-148


Final drive gear set,
recommended sequence for
adjusting
If the pinion shaft and ring gear have to be re-
adjusted, the following sequence is
recommended for maximum efficiency:
1.) Determine total shim thickness Stotal for S1 +
S2 for the specified tension of the tapered roller
bearing for differential.
2.) Determine total shim thickness S3, so that
pinion shaft obtains the specified installed
position determined by the test machine in
production.
3.) Split up total shim thickness Stotal for S1 +
S2, so that the specified torsional backlash exists
between ring gear and pinion shaft.

Note:
Overview of components and shims Page 39
-
149
.
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39-149
List of adjustments

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


Component being replaced: Ring gear
(S1 + S2)1)

Page 39
-162

Pinion shaft
(S3)1)
via deviation "r"
Page 39
-153

Backlash
checking

Page 39
-168

Final drive housing X X X
Differential housing X X
Tapered roller bearing for pinion shaft X X
Tapered roller bearing for differential X X
Final drive gear set2) X X X
Final drive cover X X 1) Shims, installation position Page 39
-150
.
2) Pinion shaft and ring gear, only replace together.
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39-155


- Bolt on 3304 bracket with two hex-head bolts M8 x 30.
- Differential must be supported when tightening nut (e.g. using
VAG1359/2 universal mount and transmission hoist VAG1383A).
- Replace pinion shaft nut.
- Tighten pinion shaft nut, until no play can be felt on pinion shaft.
- Increase tightening torque until specified friction torque is attained,
measuring friction torque several times during this process.

1) Must have run at least 50 km (30 miles)
Note:
If the specified friction torque is exceeded, the spacer sleeve must be
replaced and the adjustment repeated. A spacer sleeve that has been
over-compressed at any time cannot be reused. A - Torque gauge, 0-600 Ncm (commercially available)
B - Socket extension, 36 mm
- Adjust friction torque as follows:
New bearings
Used bearings1)
200-250 Ncm (18-22 in. lb) 30-60 Ncm (3-5 in. lb)
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39-162

Ring gear, adjusting


Adjusting differential
The ring gear must be adjusted if any of the
components have been replaced table,
Page 39
-149
.

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 the friction torque measurement.
The bearings have already been treated with a
special oil by the manufacturer.

Determining total shim thickness "Stotal" for
shims S1 + S2
(Setting preload of tapered roller bearing for
differential)
Pinion shaft removed or ring gear removed
from differential housing.

- Pry out drive flange seal using pry bar.
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- Remove differential tapered roller bearing outer
races and remove shims Page 39
-121
.
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39-163

- Press left tapered roller bearing outer race for
differential (housing side) with shim S2 into
housing Page 39
-126, Fig. 2
. To perform the
measurement use shim S2* with thickness of
1.00 mm (one 0.80 mm shim and one 0.20 mm
shim).

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

- Press in right tapered roller bearing outer race
for differential (final drive cover side) without
shims, until stop Fig. 8, Page 39
-130
.

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

- Install final drive cover and tighten bolts to 25
Nm (18 ft lb).

- Install special tools VW521/4 locking sleeve and 521/8 bushing on
housing side into differential housing.
- Turn final drive housing so final drive cover faces upward.
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39-164

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

- Place VW385/17 magnetic plate onto
differential.

- Install measuring tools.
A - Dial indicator extension approx. 30 mm long
B - Hex-head bolt M8 x 45
- Place dial indicator extension on center of VW385/17 magnetic plate.
- Set dial indicator (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 up differential without turning; read off play on dial indicator and
note.
Measurement in following example: 0.50 mm
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39-167

Measuring friction torque

Pinion shaft removed
Differential with shims S1* and S2* installed

Friction torque specifications:
Notes: - Install torque gauge, 0-600 Ncm (53 in. lb)-A- onto differential.
- Read value of dial indicator.
New bearings
Used bearings1)
150-300 Ncm (13-27 in. lb) 30-60 Ncm (3-5 in. lb)
1) Must have run at least 50 km (30 miles) 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 the friction
torque measurement. The bearings have already been treated with a
special oil by the manufacturer. If the final drive gear set (pinion shaft and ring gear) is being re-
adjusted, the adjustment of the pinion shaft should be checked
Page 39
-153
.
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39-168

Adjusting backlash
Position of ring gear in final drive housing

Pinion shaft with shim S3 installed
Differential with shims S1* + S2* installed

- Insert differential into final drive housing, install
final drive cover and tighten all bolts to 25 Nm
(18 ft lb).

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

- Assemble measuring equipment.
- Use VW382/10 dial indicator extension (6 mm flat).
- Set VW388 measuring lever to dimension -a-
Dimension -a-: 60 mm.
- 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 1 mm preload.
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39-172


Checking measurements
Notes:
Pinion shaft with shim S3 installed Differential with shims S1 + S2 installed
- Turn differential 5 turns in both directions to settle tapered roller
bearings.
- Measure backlash four times on circumference.
Specifications: 0.12-0.22 mmIf the backlash lies outside the tolerance, the adjustment must be
repeated, but the total shim thickness Stotal must remain unchanged. The individual measurements must not differ by more than 0.06 mm
from each other.
Pa
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gear set, recommended se
quence for ad
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