Replace differential gear (F23)
Remove
1. |
Dismantle transmission
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2. |
Determine setting of pressure collar and initial bearing stress
of old differential gear
• |
Remove tapered roller bearing from differential gear
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• |
Measure and note down thickness of shim (2) on transmission
housing side
– |
Remove shim
Note: The shim on the
transmission housing side (2) is used for setting the pressure
collar. The thickness of the shims must be determined with a
micrometer as they are not marked.
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• |
Measure and note down thickness of shim (1) on clutch housing
side
– |
Remove shim
Note: The shim on the
clutch housing side (1) is used for setting the initial tension of
the differential gear tapered roller bearing.
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3. |
Determine dimension (I) from the outside of the ring gear to
the bearing seating on the old differential gear
• |
Use a standard commercial digital depth micrometer
Note: Micrometer range
at least 250 mm, 0.01 mm graduations
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• |
Perform measurement 3 times - space measuring points evenly
around ring gear (arrows)
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• |
Add all measured values together
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• |
Divide by the number of measurements
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• |
Note down the average for the old differential gear
Note: The table below
is a specimen calculation. You can enter the actual measurement
results in the blank column on the right of the printout and
perform the calculation there.
Example
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Your values for the old differential
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1st measurement
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15.02mm
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+
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1st measurement
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mm
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+
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2nd measurement
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15.06mm
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+
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2nd measurement
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mm
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+
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3rd measurement
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15.05mm
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=
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3rd measurement
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mm
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=
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Total
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45.13mm
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:3=
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Total
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mm
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:3=
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Average
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15.04mm
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Average
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mm
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4. |
Remove the ring gear from the old differential gear
• |
Clamp differential gear (1) in a vice
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• |
Unscrew 10x bolt (arrow)
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• |
Drive ring gear (2) off differential gear with plastic
hammer
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• |
Clean the ring gear and check for damage
Note: An intact ring
gear can be re-used
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5. |
Determine the bearing seating distance for the new/old
differentials
• |
Use a standard commercial digital depth micrometer (1)
Note: Micrometer range
at least 250 mm, 0.01 mm graduations
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• |
Measure lengths (I, II, III)
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• |
Deduct dimension (II) and dimension (III) from dimension
(I)
Note: The table below
is a specimen calculation. You can enter the actual measurement
results in the blank column on the right of the print-out and
perform the calculation there. The calculated dimension IV is the
bearing seating distance for the differential gear concerned.
Dimension I
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210.25mm
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-
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Dimension I
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mm
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-
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Dimension II
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18.25mm
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-
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Dimension II
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mm
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-
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Dimension III
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18.30mm
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=
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Dimension III
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mm
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=
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Dimension IV
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173.70mm
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Dimension IV
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mm
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• |
Perform measurement 3 times - space measuring points evenly
around differential gear
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• |
Add all measured values together
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• |
Divide by the number of measurements
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• |
Determine and note down the average bearing seating distances
for the new and old differentials
Note: The table below
is a specimen calculation. You can enter the actual measurement
results in the blank column on the right of the printout and
perform the calculation there.
For example
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Your values
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Dimension IV 1st measurement
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90.02mm
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+
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Dimension IV 1st measurement
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mm
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+
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Dimension IV 2nd measurement
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90.05mm
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+
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Dimension IV 2nd measurement
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mm
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+
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Dimension IV 3rd measurement
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90.05mm
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=
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Dimension IV 3rd measurement
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mm
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=
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Total
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270.13mm
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:3=
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Total
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mm
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:3=
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Average
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90.04mm
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Average
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mm
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• |
Calculate the difference between the bearing seating distances
for the new/old differentials
– |
Subtract the average bearing seating distance of the old
differential from the average bearing seating distance of the new
differential
Note: If the difference
between the bearing seating distances for the old and new
differentials is more than +/- 0.04 mm, the initial stress of the
bearing for the new differential must be adjusted in a subsequent
step. If the distance is +/- 0.04 mm or less this is not necessary;
the total thickness of the shims in the old differential is then
kept the same.
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6. |
Install ring gear in new differential
• |
Clamp the new differential (2) in a vice using protective
jaws
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• |
Place the ring gear (1) on the differential gear
– |
If necessary, use a new ring gear.
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• |
Screw in 2x bolt (3) to secure
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• |
Drive ring gear onto differential gear with plastic hammer
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• |
Continue until the ring gear is touching the differential
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7. |
Insert 10x new screws (arrow)
• |
Screw in 10x bolts with locking compound
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• |
Tighten 10 bolts evenly in crosswise formation 95 Nm
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8. |
Determine dimension (I) from the outside of the ring gear to
the bearing seating on the new differential gear
• |
Use a standard commercial digital depth micrometer
Note: Micrometer range
at least 250 mm, 0.01 mm graduations
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• |
Perform measurement 3 times - space measuring points evenly
around ring gear (arrows)
|
• |
Add all measured values together
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• |
Divide by the number of measurements
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• |
Note down the average for the new differential gear
Note: The table below
is a specimen calculation. You can enter the actual measurement
results in the blank column on the right of the printout and
perform the calculation there.
Example
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Your values
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1st measurement
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15.02mm
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+
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1st measurement
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mm
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+
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2nd measurement
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15.06mm
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+
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2nd measurement
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mm
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+
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3rd measurement
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15.05mm
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=
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3rd measurement
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mm
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=
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Total
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45.13mm
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:3=
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Total
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mm
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:3=
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Average
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15.04mm
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Average
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mm
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9. |
Determine setting of pressure collar
• |
Calculate the difference between the averages
– |
Subtract the average noted down for the old differential from
the average noted down for the new differential
Note: If the difference
exceeds +0.02/-0.06mm, the pressure collar must be adjusted. If it
is less, the old shims can be re-used.
Note: The table below
can be used as a specimen calculation. The actual measurement
results can be entered in the blank column on the right of the
printout and calculation performed.
Average
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New differential
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15.16mm
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-
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-
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Average
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Old differential
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15.04mm
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=
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=
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Difference in dimensions
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+ 0.12 mm
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10. |
Insert 2x shim (1, 4)
Important: Make sure that the
correct shims are fitted on the clutch housing side and the
transmission housing side
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• |
If necessary, reset pressure collar
– |
Determine the thickness of the new shims and insert them
Note: If the difference
between the dimensions is positive, choose a shim (4) that is the
same dimension thicker than the old one. If the difference is
negative, a correspondingly thinner shim must be used. The total
thickness of both shims must remain constant as this determines the
prestressing of the differential gear tapered roller bearing.
Therefore if a thicker shim (4) is used on the transmission housing
side, fit a clutch housing side shim (1) that is thinner by the
same amount. If a thinner shim is used on the transmission housing
side a correspondingly thicker shim must be installed on the clutch
housing side.
Note: The shims can be
obtained from "Aftersales". The thickness of the shims (2) must be
determined with a micrometer (3) as there is no marking on them
Note: The table below
contains a few examples from the range of shims that can be
supplied. When adjusting, the shims must be selected to achieve the
smallest tolerance possible. Undamaged used shims can be
re-used.
Difference in dimensions
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Shim (on transmission housing side)
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Shim (on clutch housing side)
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- 0.25 mm
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old
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0.90mm
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new
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0.65 mm
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old
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0.75mm
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new
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1.00mm
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+ 0.20 mm
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old
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0.90mm
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new
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1.10 mm
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old
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0.75mm
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new
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0.55mm
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+ 0.13mm
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old
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0.90mm
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new
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1.05 mm
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old
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0.75mm
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new
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0.60mm
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+ 0.12 mm
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old
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0.90mm
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new
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1.00mm
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old
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0.75mm
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new
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0.65 mm
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11. |
If necessary: adjust initial pressure of differential gear
tapered roller bearing
Note: If the difference
between the bearing seating distances for the old and new
differentials is more than +/- 0.04 mm, the initial stress of the
bearing for the new differential must be adjusted now. If the
distance is +/- 0.04 mm or less this is not necessary; the total
thickness of the shims in the old differential is then kept the
same.
Important: The shim (4) on the
transmission housing side that is determined for the pressure
collar setting is not changed for setting the initial stress of the
bearing.
|
• |
Determine the thickness of the new shim (1) on the clutch
housing side
– |
Compare the average bearing seating distance noted down for the
new differential with the average noted down for the old
differential.
Note: If the value for
the new differential is greater than that for the old one, the
clutch housing side shim chosen must be thinner by the difference
in the values. If the bearing seating difference for the new
differential is less than that for the old one, the clutch housing
side shim chosen must be correspondingly thicker.
Note: The shims can be
obtained from "Aftersales". The thickness of the shims (2) must be
determined with a micrometer (3) as there is no marking on them
Note: The table below
contains a few examples from the range of shims that can be
supplied. When adjusting, the shims must be selected to achieve the
smallest tolerance possible. Undamaged used shims can be
re-used.
Average bearing seating distance, old
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Shim (on clutch housing side), old
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Average bearing seating distance, new
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Shim (on clutch housing side), new
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90.10 mm
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0.75mm
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90.03mm
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0.80mm
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90.07mm
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0.85mm
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90.15mm
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0.75mm
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90.21mm
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0.90mm
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90.08mm
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1.05 mm
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12. |
When the differential gear tapered roller bearing is being
replaced, remove 2 differential gear tapered roller bearing outer
rings from the clutch housing and the transmission housing
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Install
13. |
Install differential gear tapered roller bearing
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14. |
Assemble transmission
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