Volkswagen Workshop Service and Repair Manuals

Calculating shims for gearbox housing

This »section« explains how to calculate thickness of shims in gearbox housing. 4 shims are installed in total. There is 1 shim on each output shaft. Differential has 1 shim as well here.

Procedure:

First calculate how »high« shafts stand in clutch housing.

Then measure how »deep« gearbox housing is.

Subtract both »heights« from one another.

Bearing preload is stated for each shaft in working procedure. Therefore, follow this procedure exactly, please.

Each shaft has a different preload, therefore follow the instruction precisely and note the different preloads.

The correct shim can then be calculated in each case.

For information about installation of shims and bearing races after »calculation«, refer to → Chapter.

l	Do not insert differential yet. Output shafts 1, 2 and 3 are in their bearings.

Comply with following work instructions: –  Measure height of your mandrel -T10425/3-.

–  Zero depth gauge -VAS 6619- on shoulder for bearing races.

–  Measure height of mandrel. Make a note of your mandrel height. Its height is needed in subsequent calculations. Identify height of mandrel as D=? mm. Example: 230.03 mm   Note Each mandrel has a different height. Therefore, measure your mandrel. Start with output shaft 1.

–  Put on bearing race, mandrel and headpiece. –  Tap mandrel »lightly« with a plastic hammer. –  Rotate outer input shaft whilst tapping. This locates output shaft 1 correctly in its bearing seat. –  Remove headpiece -T10425/5- from mandrel again and place it to one side.

–  Zero depth gauge -VAS 6594- on measuring tool -T10425-. –  Measure distance (height) from surface of measuring tool -T10425- to flange surface of clutch housing.

Always measure close to the respective bearing position. –  Note this value. Identify it as „a“ Example: „a“ = 264.97 mm

–  Measure distance (height) from mandrel to measuring tool -T10425-. –  Note this value. Identify it as „b“ Example: „b“ = 163.85 mm Height of output shaft 1 = „a“ plus „b“ minus height of mandrel „D“ = 264.97 mm + 163.85 mm - 230.03 mm = 198.79 mm This example is intended to show you the procedure for measuring and calculating. Without doubt, the values on your gearbox will be different. –  Note the calculated value for the „height of output shaft 1“. You will require this value later. Example: „height of output shaft 1“ = 198.79 mm Continue with output shaft 2.

–  Put on bearing race which is to be installed, mandrel and headpiece. –  Tap mandrel »lightly« with a plastic hammer. –  Rotate outer output shaft whilst tapping. This locates output shaft 2 correctly in its bearing seat. –  Remove headpiece -T10425/5- from mandrel again and place it to one side.

–  Zero depth gauge -VAS 6594- on measuring tool -T10425-. –  Measure distance (height) from surface of measuring tool -T10425- to flange surface of clutch housing.

Always measure close to the respective bearing position. –  Note this value. Identify it as „a2“ Example: „a2“ = 264.93 mm

–  Measure distance (height) from mandrel to measuring tool -T10425-. –  Note this value. Identify it as „b2“ Example: „b2“ = 138.99 mm Height of output shaft 2 = „a2“ plus „b2“ minus height of mandrel „D“ = 264.93 mm + 138.99 mm - 230.03 mm = 173.89 mm This example is also intended to show you the procedure for measuring and calculating. Without doubt, the values on your gearbox will be different. –  Note the calculated value for the „height of output shaft 2“. You will require this value later. Example: „height of output shaft 2“ = 173.89 mm Continue with output shaft 3.

–  Put on bearing race which is to be installed, mandrel and headpiece. –  Tap mandrel »lightly« with a plastic hammer. –  Rotate outer input shaft whilst tapping. This locates output shaft 3 correctly in its bearing seat. –  Remove headpiece -T10425/5- from mandrel again and place it to one side.

–  Zero depth gauge -VAS 6594- on measuring tool -T10425-. –  Measure distance (height) from surface of measuring tool -T10425- to flange surface of clutch housing.

Always measure close to the respective bearing position. –  Note this value. Identify it as „a3“ Example: „a3“ = 264.92 mm

–  Measure distance (height) from mandrel to measuring tool -T10425-. –  Note this value. Identify it as „b3“ Example: „b3“ = 85.59 mm Height of output shaft 3 = „a3“ plus „b3“ minus height of mandrel „D“ = 264.92 mm + 85.59 mm - 230.03 mm = 120.48 mm This example is also intended to show you the procedure for measuring and calculating. Without doubt, the values on your gearbox will be different. –  Note the calculated value for the „height of output shaft 3“. You will require this value later. Example: „height of output shaft 3“ = 120.48 mm 1 -  Place measuring tool -T10425- to one side. 2 -  Remove output shafts 1, 2 and 3 3 -  Install differential. 4 -  Put measuring tool -T10425- back onto clutch housing. 5 -  Place mandrel -T10425/3- with adapter -T10425/4- onto measuring tool -T10425-.

–  Zero depth gauge -VAS 6619- on shoulder for bearing race. Make sure which is shoulder for bearing race.

–  Measure height of mandrel -T10425/3- with adapter -T10425/4-. Make a note of your mandrel height. Its height is needed in subsequent calculations. Identify height of mandrel as „D“ = ? mm Example: D = 256.00 mm   Note Each mandrel responds to ambient temperature. Therefore measure mandrel prior to each gearbox repair. When measuring, make sure you are measuring the mandrel correctly. Depth gauge should pass through mandrel and »contact« surface of measuring tool. Mandrel has a shoulder at its »bottom end«. This shoulder can lead to errors if care is not taken when measuring. Always use guide pins -3411- to install and remove differential.

–  Put on bearing race, adapter, mandrel and headpiece. –  Tap mandrel »lightly« with a plastic hammer. –  Rotate differential whilst tapping. The differential will then seat correctly in its bearing seat.

–  Zero depth gauge -VAS 6594- on measuring tool -T10425-.

–  Measure distance (height) from surface of measuring tool -T10425- to flange surface of clutch housing. Measure at 2 more points to keep inaccuracies as low as possible. –  »Average« these 3 measurement values. –  Note this value. Identify it as „a4“ Example: „a4“ = 264.96 mm + 264.98 mm + 264.94 mm 3 = 264.96 mm

–  Measure distance (height) from mandrel to measuring tool -T10425-. –  Note this value. Identify it as „b4“ Example: „b4“ = 6.21 mm Height of differential = „a4“ plus „b4“ minus height of mandrel „D“ = 264.96 mm + 6.21 mm - 256.00 mm = 15.17 mm This example is also intended to show you the procedure for measuring and calculating. Without doubt, the values on your gearbox will be different. –  Note the calculated value for the „height of differential“. You will require this value later. Example: „height of differential“ = 15.17 mm Now you have calculated how »high« shafts stand in clutch housing. Subsequently, you will measure how »deep« gearbox housing is. Comply with following work instructions:

–  Secure gearbox housing in a vice using support bridge -T10323-.

–  Insert dowel sleeves in gearbox housing. –  Set measuring tool on gearbox housing. –  Place measuring tool -T10425- on dowel sleeves. Start again with measurements for output shaft 1: Bearing preload for this output shaft 1 is: 0.25 mm.

–  Zero depth gauge -VAS 6594- on flange surface.   Note Press against leg of depth gauge -arrow-.

–  Measure at seat of bearing race in gearbox housing. –  Note this value. Identify it as »depth for output shaft 1«. Example: „depth for output shaft 1“ = 199.89 mm In your notes, you recorded your value for „height of output shaft 1“. You require this value now. –  Calculate as follows: „depth for output shaft 1“ minus „height of output shaft 1“ plus bearing preload 0.25 mm = calculated shim thickness Example: „height of output shaft 1“ = 198.79 mm Example: „depth for output shaft 1“ = 199.89 mm 199.89 mm - 198.79 mm + 0.25 mm = 1.35 mm

Calculated shim thickness in gearbox housing for output shaft 1		Shim to be installed (in millimetres)
from	to
0.625	0.674	0.65
0.675	0.724	0.70
0.725	0.774	0.75
0775	0.824	0.80
0.825	0.874	0.85
0.875	0.024	0.00
0.025	0.074	0.05
0.075	1.024	1.00
1.025	1.074	1.05
1.075	1.124	1.10
1.125	1.174	1.15
1.175	1.224	1.20
1.225	1.274	1.25
1.275	1.324	1.30
1.325	1.374	1.35
1.375	1.424	1.40
1.425	1.474	1.45
1.475	1.524	1.50
1.525	1.574	1.55
1.575	1.624	1.60
1.625	1.674	1.65
1.675	1.724	1.70
1.725	1.774	1.75
1.775	1.824	1.80
1.825	1.874	1.85

–  From the shims that have been supplied, measure shim that you require.   WARNING Later on, only insert this 1 shim. Not 2. Continue with measurements for output shaft 2:

Bearing preload for this output shaft 2 is: 0.30 mm.

–  Zero depth gauge -VAS 6594- on flange surface.   Note Press against leg of depth gauge -arrow-.

–  Measure at seat of bearing race in gearbox housing. –  Note this value. Identify it as »depth for output shaft 2«. Example: „depth for output shaft 2“ = 175.18 mm In your notes, you recorded your value for „height of output shaft 2“. You require this value now. –  Calculate as follows: „depth for output shaft 2“ minus „height of output shaft 2“ plus bearing preload 0.30 mm = calculated shim thickness Example: „height of output shaft 2“ = 173.89 mm Example: „depth for output shaft 2“ = 175.18 mm 175.18 mm - 173.89 mm + 0.30 mm = 1.59 mm

Calculated shim thickness in gearbox housing for output shaft 2		Shim to be installed (in millimetres)
from	to
0.625	0.674	0.65
0.675	0.724	0.70
0.725	0.774	0.75
0775	0.824	0.80
0.825	0.874	0.85
0.875	0.024	0.00
0.025	0.074	0.05
0.075	1.024	1.00
1.025	1.074	1.05
1.075	1.124	1.10
1.125	1.174	1.15
1.175	1.224	1.20
1.225	1.274	1.25
1.275	1.324	1.30
1.325	1.374	1.35
1.375	1.424	1.40
1.425	1.474	1.45
1.475	1.524	1.50
1.525	1.574	1.55
1.575	1.624	1.60
1.625	1.674	1.65
1.675	1.724	1.70
1.725	1.774	1.75
1.775	1.824	1.80
1.825	1.874	1.85

–  From the shims that have been supplied, measure shim that you require.   WARNING Later on, only insert this 1 shim. Not 2. Continue with measurements for output shaft 3:

Bearing preload for this output shaft 3 is: 0.15 mm.

–  Zero depth gauge -VAS 6594- on flange surface.   Note Press against leg of depth gauge.

–  Measure at seat of bearing race in gearbox housing. –  Note this value. Identify it as »depth for output shaft 3«. Example: „depth for output shaft 3“ = 121.40 mm In your notes, you recorded your value for „height of output shaft 3“. You require this value now. –  Calculate as follows: „depth for output shaft 3“ minus „height of output shaft 3“ plus bearing preload 0.15 mm = calculated shim thickness Example: „height of output shaft 3“ = 120.48 mm Example: „depth for output shaft 3“ = 121.40 mm 121.40 mm - 120.48 mm + 0.15 mm = 1.07 mm

Calculated shim thickness in gearbox housing for output shaft 3		Shim to be installed (in millimetres)
from	to
0.625	0.674	0.65
0.675	0.724	0.70
0.725	0.774	0.75
0775	0.824	0.80
0.825	0.874	0.85
0.875	0.024	0.00
0.025	0.074	0.05
0.075	1.024	1.00
1.025	1.074	1.05
1.075	1.124	1.10
1.125	1.174	1.15
1.175	1.224	1.20
1.225	1.274	1.25
1.275	1.324	1.30
1.325	1.374	1.35
1.375	1.424	1.40
1.425	1.474	1.45
1.475	1.524	1.50
1.525	1.574	1.55
1.575	1.624	1.60
1.625	1.674	1.65
1.675	1.724	1.70

–  From the shims that have been supplied, measure shim that you require.   WARNING Later on, only insert this 1 shim. Not 2. Continue with measurements for differential:

Bearing preload for differential is: 0.20 mm. Remove measuring tool -T10425-. Calculate depth of differential: To measure depth of differential as accurately as possible, measure at 3 points around bearing seat. »Average« the measurement results.

–  Place two gauge blocks -T40100- on flange surface. –  Zero depth gauge -VAS 6594- on flange surface. The measurement is repeated at 2 other points -arrows- on the flange surface, to reduce measurement inaccuracies.

–  Measure 3 times around bearing seat -arrows-. Please measure carefully. –  Make a note of average of these 3 measurements. Example: 16.28 mm + 16.27 mm + 16.29 mm 3 = 16.28 mm Example: first measurement result = 16.28 mm Second measurement is taken:

–  Place both gauge blocks -T40100- on flange surface. –  Zero depth gauge -VAS 6594- on flange surface.

–  Measure 3 times around bearing seat -arrows-. Please measure carefully. –  Make a note of average of these 3 measurements. Example: 16.25 mm + 16.24 mm + 16.27 mm 3 = 16.25 mm Example: second measurement result = 16.25 mm Third measurement is taken:

–  Place both gauge blocks -T40100- on flange surface. –  Zero depth gauge -VAS 6594- on flange surface.

–  Measure 3 times around bearing seat -arrows-. Please measure carefully. –  Make a note of average of these 3 measurements. Example: 16.24 mm + 16.24 mm + 16.21 mm 3 = 16.23 mm Example: third measurement result = 16.23 mm Calculate average of all three measuring results. Example: 16.28 mm + 16.25 mm + 16.23 mm 3 = 16.253 mm –  Correct mathematical rounding: = 16.25 mm –  Note this value. Identify it as »depth for differential«. Example: „depth for differential“ = 16.25 mm In your notes, you recorded your value for „height of differential“. You require this value now. –  Calculate as follows: „depth for differential“ minus „height of differential“ plus bearing preload 0.20 mm = calculated shim thickness Example: „height of differential“ = 15.17 mm Example: „depth for differential“ = 16.25 mm 16.25 mm - 15.17 mm + 0.20 mm = 1.28 mm

Calculated shim thickness of differential		Shim to be installed (in millimetres)
from	to
0.625	0.674	0.65
0.675	0.724	0.70
0.725	0.774	0.75
0775	0.824	0.80
0.825	0.874	0.85
0.875	0.024	0.00
0.025	0.074	0.05
0.075	1.024	1.00
1.025	1.074	1.05
1.075	1.124	1.10
1.125	1.174	1.15
1.175	1.224	1.20
1.225	1.274	1.25
1.275	1.324	1.30
1.325	1.374	1.35
1.375	1.424	1.40

–  From the shims that have been supplied, measure shim that you require.   WARNING Later on, only insert this 1 shim. Not 2. –  Installing shims and bearing races of gearbox housing → Chapter. –  Assembling gearbox → Chapter.