Iveco Stralis AT/AD. Manual - part 171

To determine the thickness of the shim pack to be
interposed between bearing cage and differential carrier
proceed as follows:

measure the thickness of the shim pack removed
with the old final drive gear set. Use a micrometer or
other suitable gauge and record the value found;

Pinion/crown wheel set manufacturing and inspection
month and year.

Specified pinion/crown wheel set clearance.

Part number and tooth combination number are stamped on
threaded end of all pinions. Number may alternatively be
located on outer diameter of crown wheel. On any
pinion/crown wheel set, crown wheel will always bear an even
stamped

category

number

(e.g.

36786),

whereas

corresponding pinion will bear an odd number (e.g. 36787).

Every crown wheel is marked with a variation number which
indicates the nominal assembly distance. Use this number to
calculate the thickness of the shim pack that is interposed
between pinion bearing cage and differential carrier.
The variation number (CP + 0,1 or CP - 0,1) is stamped on
crown wheel outer face.

variation number needed to determine the thickness of
the shim pack interposed between pinion bearing cage
and differential carrier (in the example below, this number
is identified as CP).

part number;

tooth combination number.
This number (example: 12/41) indicates that the pinion
has 12 teeth and the crown wheel 41;

pinion/crown wheel pair set number.
All final drive sets are available as pairs: therefore pinion
and crown wheel bear the same number which is
stamped on head end for pinions and the outer face for
crown wheels;

Allow the bevel crown wheel to cool before positioning the
screws. Use torque wrench (1) to tighten self locking nuts (2)
to the specified torque.

With self-locking nut and screw 310

± 15 Nm;

With screw, washer and nut:
first stage (pre-tightening)

100 Nm

second stage (angular tightening)

100

36325

36324

Figure 80

Figure 81

Heat bevel crown wheel (1) in a circulating air oven to a tem-
perature of 100

˚C for about 15’ and position it on its seating

on the gear cage, ensuring that the holes for the bevel crown
wheel/gear cage attachment screws are lined up.

ASSEMBLING DIFFERENTIAL CASING
Calculating bevel pinion position in differential
casing

Figure 82

19416

1,2

1,2,3

1,2,3,4,5,6

OPTION

If a new final drive set is installed, it will be necessary to know
the meaning of the markings on pinion and crown wheel in
order to position the pinion correctly:

Never use a pinion and crown wheel set unless both
components have the same number.

read the CP marked on pinion to be replaced: if it is
a plus (+) number or a minus (-) number respectively
subtract or add it from the value obtained under 1.
above;
Take note of the result.

The value obtained in 2. will be used to calculate the
thickness of the shim to be interposed between pinion
bearing cage and differential carrier for correct new
final drive assembly.

read the CP marked on the new pinion.
Either add or subtract this value - depending on
whether the sign is a plus or a minus - to or from the
value noted under 2. above.
The result indicates the thickness which the new shim
pack should have.

Refer to the following examples which cover all the possible
calculation cases.

134

AXLES IN TANDEM MERITOR RP 160 E (R 2478) (INTERMEDIATE)

TRALIS

AT/AD

Figure 83

COMPUTATIONAL EXAMPLES

The difference between the value of the thickness of
the new pack and that of the old one must be added
to or subtracted from, depending on the case, the
thickness of the adjustment ring (6, Figure 84).

Place the bevel pinion position adjustment rings (4) in the box
and, using grip 99370007 (1) and drift 99374094 (2), mount
the external ring (3) for the bevel pinion bearing.
Fit remaining bearing cups using drift 99374093.

36383

77239

Figure 84

Measure the thickness of the adjustment ring (6) found on
removal and note down the value (dimension A).
Tighten the tool 99395027 (8) in a vice and place the following
on it:

- the bearing (7) on the pinion side;
- the ring (6) previously measured.
- the gear (5);
- the spacer (4);
- the bearing (3).
Screw down the ring nut (2) and tighten it fully.
Position part (1) of tool 99395027 (8), equipped with a dial
gauge, on the bearing (3) and reset the dial gauge on the end
of the tool (8).
Then remove:

- the part (1);
- the ring nut (2);
- the bearing (3);
- the spacer (4);
- the gear (5);
- the ring (6) the bearing (7) from the tool (8).

Figure 85

77241

Insert the tool 99394027 (8, Figure 84) in the differential gear
housing, comprehensive of the bearing (7, Figure 84), ring (6),
gear (5), spacer (4), bearing (3). Screw down the ring nut (1)
on the tool 99394027.

Determining the thickness of the bevel pinion
bearing clearance adjustment rings

AXLES IN TANDEM MERITOR RP 160 E (R 2478) (INTERMEDIATE)

135

TRALIS

AT/AD

Case 1:

Original shim pack thickness

0.76

CP marked on pinion +2

+0.05

Resulting value

0.81

CP marked on new pinion +5

-0.12

Thickness for new shim pack

0.69

Case 2:

Original shim pack thickness

0.76

CP marked on pinion -2

-0.05

Resulting value

-0.71

CP marked on new pinion +5

-0.12

Thickness for new shim pack

-0.59

Case 3:

Original shim pack thickness

-0.76

CP marked on pinion + 2

+0.05

Resulting value

0.81

CP marked on new pinion -5

+0.12

Thickness for new shim pack

0.93

Case 4:

Original shim pack thickness

-0.76

CP marked on pinion -2

-0.05

Resulting value

0.71

CP marked on new pinion -5

+0.12

Thickness for new shim pack

0.83

36385

78313

36386

36387

Figure 86

Figure 87

Figure 88

Figure 89

Reposition part (1) of tool 99395027, with the dial gauge
previously reset on the bearing (3) and measure any difference
(dimension B).

The thickness S of the ring, or of the adjustment rings, is given
by the following formula:

S = A - (

± B) + C

where:

A = Thickness of the adjustment ring(s) fitted to reset the
dial gauge;

B = Value of the difference measured;

C = 0.2 mm coefficient that takes account of the
expansion of the bearings due to the interference of
assembly on the bevel pinion.

Heat the bearing (2) to 100

°C for 15 min. and, with a specific

drift, fit it on the bevel pinion.

Screw down the ring nut (2, Figure 87) tightening it until, with
a dynamometer, you measure a rolling torque of:

- 1.10 to 5.00 Nm if the bearings are new,

- 1.68 to 3.39 Nm if the bearings have already been used.

First example:

A = 13.12 mm
B = + 0.13 mm
C = 0.2 mm

S = 13.12 - (+ 0.13) + 0.2 =
S = 13.12 — 0.13 + 0.2 = 13.19 mm.

Second example:

A = 13.12 mm
B = - 0.13 mm
C = 0.2 mm

S = 13.12 - (- 0.13) + 0.2 =
S = 13.12 + 0.13 + 0.2 = 13.45 mm.

Remove from the box the tool 99395027 (8, Figure 84) and
take out the bearings, spacers and gear as shown in the figure.

Insert the bevel pinion (3) in the box, simultaneously keying
onto it the adjustment ring (1) of the thickness determined in
the preceding measurements and the gear (2); screw the part
99345029 (4) onto the bevel pinion (3).

136

AXLES IN TANDEM MERITOR RP 160 E (R 2478) (INTERMEDIATE)

TRALIS

AT/AD

Block rotation of the bevel pinion with the tool S.P. 2373 (1).
Screw down the nut fastening the bevel pinion bearings and
tighten it to the prescribed torque.

77242

77237

20670

94191

Figure 90

Figure 91

Figure 92

Figure 93

Block rotation of the bevel pinion with the tool S.P. 2373 (5).
Screw down the inserter 99345098 (4) onto the part (4,
Figure 89) and fully drive in the gear (3).
Remove the inserter (4).
Fit on the spacer ring (1).
Heat the bearing (2) to 100

°C for 15 min. and fit it onto the

pinion.
Screw the inserter (4) back onto the part (4, Figure 89) and
take the bearing (2) into contact with its seat.

To tighten the nut use the wrench 99355069 (2)
torque wrench and multiplier 99389816 (3).

Position the caps taking care to make the reference marks
coincide.
Insert the screws, together with the washers, and tighten
them, using a torque wrench, to the prescribed torque.
Then check that the external rings of the bearings slide, with
a light pressure, in their respective seats without sticking.
Again unscrew the fastening screws with the washers and
remove the caps.

Using the hook (1), lift the gear housing (2) previously
assembled and position it on the differential casing (3).

Figure 94

77245

Position the caps (2), screw down the screws (1) with the
washers and tighten them to the prescribed torque.

AXLES IN TANDEM MERITOR RP 160 E (R 2478) (INTERMEDIATE)

137

TRALIS

AT/AD

Content .. 169 170 171 172 ..