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Replace differential gear (F23)
 Remove
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| 2. |
Dismantle transmission
Note: When replacing
the differential, the thrust collar setting must be determined and
adjusted if necessary. The tapered roller bearings of the
differential must be removed to do this 
| 1. |
Differential with differential ring gear |
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|
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Important: For determination of
the shims for the bearing pre-tension, the determination on the
transmission side for adjustment of the pressure comb is always
given priority.
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| 3. |
Check adjustment of thrust collar
| • |
Measure the size of the shim on the transmission housing side
(2)
Note: Is used for
adjusting the thrust collar.
|
| • |
Measure size of the shim on the clutch housing side (1)
Note: Is used for
adjusting the bearing pre-tensioning of the tapered roller bearing
of the differential
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|
|
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| 4. |
Measurement (I) Distance between the height of the ring gear
and the seat of the tapered roller bearing, measure shim on
transmission housing side
Note: With a standard
commercial digital depth gauge with a measuring range of at least
250 mm and graduations of 0.01 mm, determine the measurement (I),
distance between the height of the ring gear and the seat of the
tapered roller bearing for the differential on the housing
side.
| • |
Undertake measurement at three measuring points (arrows) evenly
distributed around the ring gear and differential
|
| • |
Add up measured values and divide by the number of
measurements
Note: This method of
calculation is illustrated in the table below.
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|
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| 5. |
Measured values
Note: The purpose of
the following tables is to explain the pressure comb adjustment
using an example calculation.
The measured values in the left hand table serve as an example of
the calculation used for evaluating the measurement.
You can enter your measured results in the right hand table (as a
print-out) to make the evaluation easier.
|
Example:
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Measurement:
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Your values
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1st measurement
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15.02 mm
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1st measurement
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|
|
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2nd measurement
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+
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15.06 mm
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2nd measurement
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+
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|
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3rd measurement
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+
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15.05 mm
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3rd measurement
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+
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Total value
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=
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45.13 mm
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Total value
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=
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Mean value
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:3 =
|
15.04 mm
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Mean value
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:3 =
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|
Note: This measurement
is undertaken on the old differential with the old ring gear, then
the new differential is measured, this can be with the new or old
ring gear depending on whether the ring gear also has to be
replaced. Ring Gear, Remove/Install
If a value deviates by more than 0.08 mm from the other values of
this measurement, the measurement must be repeated as a measurement
error has occurred.
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| 6. |
Determine difference measurement
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Table for example of calculation of difference
measurement:
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Mean value, new shaft
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15.16 mm
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Mean value, old shaft
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-
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15.04 mm
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± Difference
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=
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+ 0.12 mm
|
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Table for your difference measurement
calculation:
|
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Mean value, new shaft
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|
|
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Mean value, old shaft
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-
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± Difference
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=
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Note: The total
thickness of the two shims remains constant because this produces
the bearing pre-tensioning for the tapered roller bearings.
| • |
Deduct mean value for the old differential from the mean value
for the new differential
Note: If the difference
measurement between the old and the new differential is more than
(+0.02/-0.06) mm, the thrust collar must be adjusted.
|
| • |
If the difference measurement is positive (+), the shim (on the
transmission housing side) (4) must be selected so that it is the
same measurement thicker
|
| • |
If the difference measurement is negative (-) (on the
transmission housing side) (4) the shim must be selected so that it
is the same measurement thinner
|
| • |
if the shim (on the transmission housing side) (4) is thicker,
the shim (on the clutch housing side) (1) must be selected so that
it is the same measurement thinner
|
| • |
if the shim (on the transmission housing side) (4) is thinner,
the shim (on the clutch housing side) (1) must be selected so that
it is the same measurement thicker
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| 7. |
Determine actual measurement of the shims (2)
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Difference measurement
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Shim (transmission housing side)
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Shim (clutch housing side)
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- 0.25 mm
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old
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0.90 mm
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new
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0.65 mm
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old
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0.75 mm
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new
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1.00 mm
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+ 0.20 mm
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old
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0.90 mm
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new
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1.10 mm
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old
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0.75 mm
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new
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0.55 mm
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+ 0.13 mm
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old
|
0.90 mm
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new
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1.05 mm
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old
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0.75 mm
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new
|
0.60 mm
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+ 0.12 mm
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old
|
0.90 mm
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new
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1.00 mm
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old
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0.75 mm
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new
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0.65 mm
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Note: During adjustment,
the shims must be selected so that the smallest possible tolerance
is achieved.
Used shims can be re-used for subsequent adjustment operations,
provided that they have not been damaged.
The shim (clutch housing side) is only altered in the subsequent
adjustment of the bearing pretension for the differential
regardless of the shim (transmission housing side).
Note: Appropriate shims
can be ordered via the "Service" Department.
| • |
The actual measurement of the shims is determined using a
micrometer (3) since the shims are not labelled.
|
|
|
|
Important: The next measurement
is carried out on the old and new differential (2) without
differential tapered roller bearing and without ring gear. However,
the measurement for the shim (transmission housing side) that has
already been determined must also be taken into account; this
measurement must be given highest priority for adjustment
operations on the differential and must not be altered in the
subsequent adjustment.
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| 8. |
Measure differential
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Example:
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|
|
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Measurement:
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Your values
|
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Measurement I
|
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210.25 mm
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Measurement I
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|
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Measurement II
|
-
|
18.25 mm
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Measurement II
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-
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Measurement III
|
-
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18.30 mm
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Measurement III
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-
|
|
|
Measurement IV
|
=
|
173.70 mm
|
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Measurement IV
|
=
|
|
Note: Measure with a
standard commercial digital depth gauge (1) with a measuring range
of at least 250 mm and graduations of 0.01 mm
| • |
Determine measurement of differential (I), (II) and (III)
3x
|
| • |
Deduct measurement I from measurement II and III
Note: This method of
calculation is illustrated in the table below.
Measurement IV corresponds to the distance between the seats of the
tapered roller bearings of the differential
|
|
|
| 9. |
Measure old differential
- Undertake measurement at three measuring points evenly
distributed over the differential
- Add calculated values, measurement IV, and divide by the number
of measurements
Note: This method of
calculation is illustrated in the table below.
|
Example:
|
|
|
|
|
Measurement:
|
|
Your values
|
|
1st measurement
|
Measurement IV
|
|
90.02 mm
|
|
1st measurement
|
Measurement IV
|
|
|
|
2nd measurement
|
Measurement IV
|
+
|
90.06 mm
|
|
2nd measurement
|
Measurement IV
|
+
|
|
|
3rd measurement
|
Measurement VI
|
+
|
90.05 mm
|
|
3rd measurement
|
Measurement IV
|
+
|
|
|
Total value
|
|
=
|
270.13 mm
|
|
Total value
|
|
=
|
|
|
Mean value
|
|
:3 =
|
90.04 mm
|
|
Mean value
|
|
:3 =
|
|
Note: This measurement
is performed in the same way on the new differential. If the height
difference between the old and the new differential is greater than
± 0.04 mm, the differential bearing pre-tension must be
adjusted. If the height difference is less than ± 0.04 mm,
the adjustment for the differential bearing pre-tension is
retained. Only the measurement of the shim (clutch housing side) is
adapted to the measurement of the shim (transmission housing side).
This is illustrated in the following table.
|
Shim (transmission housing side) old
|
Shim (clutch housing side) old
|
|
Shim (transmission housing side) new
|
Shim (clutch housing side) new
|
|
0.90 mm
|
1.10 mm
|
|
1.00 mm
|
1.00 mm
|
|
1.25 mm
|
0.75 mm
|
|
1.10 mm
|
0.90 mm
|
Note: The total
thickness of the two shims remains the same as long as the height
of the differential (measurement IV) does not change or the
deviation remains less than ± 0.04 mm. The determination of
the shims for the adjustment of the differential bearing pretension
is described in the table below.
The total measurement of the shim + height of differential
(measurement IV) = remains constant ± 0.04 mm, for new and
old differential. This means that the differential and shim
assembly for the new differential must have the same measurement as
that of the old differential. The adjustment has then been
performed correctly.
The measurement determined previously for the shim (on the
transmission housing side) may not be changed.
| • |
If measurement IV on the new differential is greater than
measurement IV on the old differential, the shim (clutch housing
side) is selected thinner by the difference in measurement IV
|
| • |
If the new differential is shorter than the old differential,
the shim (clutch housing side) is selected thicker by the
difference in the measurement (IV)
|
|
Install
| 10. |
A few examples for using the shims are listed in the table
below.
|
Measurement IV (old)
|
Shim (clutch housing side) old
|
Measurement IV (new)
|
Shim (clutch housing side) new
|
|
90.10 mm
|
0.75 mm
|
90.03 mm
|
0.80 mm
|
|
90.07 mm
|
0.85 mm
|
90.15 mm
|
0.75 mm
|
|
90.21 mm
|
0.90 mm
|
90.08 mm
|
1.05 mm
|
|
| 11. |
The smallest possible tolerance is desirable for the
adjustment. In doing so, the shim (transmission housing side) must
not altered, since the pressure collar adjustment has already been
made.
|
|
| 12. |
Overview
Note: If the
differential is to be replaced re-using the run-in inner tapered
roller bearing races for the differential (2 and 3) these must be
changed over
If using new inner tapered roller bearing races, the outer tapered
roller bearing races of the differential (1 and 4) must also be
replaced
|
| 13. |
Attach differential ring gear
|
|
| 14. |
Assemble transmission
|
|
