1999 AUDI A4 01A Transmission Final Drive Gear Set Workshop Manual

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
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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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39-169

- Turn ring gear back until contact is made
against opposite tooth flank (backlash).

- Read value of dial indicator and note.

-
Turn ring gear 1/2-turn (90 ) each time and
repeat measurements 3 times.
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 set itself is
not correct. Check installation, replace final
drive set if necessary.

Determining average backlash

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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39-170

Determining thickness of shim "S2"

Formula:
S2
=
S2* - backlash + lift

Example:

Inserted shim S2* 1.00 mm
- Average backlash 0.29 mm
+ Lift (constant) 0.15 mm
= Thickness of shim S2 0.86 mm

- Determine shim(s) according to table. Part
numbers parts catalog
The following shims are available for "S2"

Shim thickness (mm)1)
0.15 0.50 1.50
0.20 0.80
0.25 1.00
1) Using the shim tolerance variations it is
possible to find the exact shim thickness required,
insert two shims if necessary.
Pa
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39-171

Determining thickness of shim "S1"

Formula:
-S1-
=
Stotal - S2

Example:

Total shim thickness Stotal for S1 +
S2 1.80
mm
- Thickness of shim S2 0.86
mm
= Thickness of shim S1 0.94
mm

- Determine shim(s) according to table. Part
numbers parts catalog.
The following shims are available for "S1"

Shim thickness (mm)1)
0.15 0.50 0.90
0.20 0.60 1.00
0.30 0.70 1.20
0.40 0.80
1) Using the shim tolerance variations it is
possible to find the exact shim thickness required,
Pa
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insert two shims if necessary.
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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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justin
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11/20/2002 htt
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yp
e=re
pair&id=AUDI.B5.TM02.39.18