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4-8
UNACCEPTABLE PATTERN
An erratic tooth pattern on a
hunting gear set indicates gear set
runout and is caused by one of the
following conditions:
1.
Foreign matter between diff-
erential hemisphere gear locating
base and back face of crown wheel.
2. Faulty gear set
NON HUNTING GEAR SET
In a non hunting type gear set,
any <>ne pinion gear tooth comes
into contact with only a few
ring
gear teeth
.
In
this
type, only one
revolution of the ring gear is re-
quired to make all possible tooth
contact combinations.
ACCEPTABLE PATTERNS
The
drive
patterns
shown
in
Figs.
7 and 8 were rolled on two
different
non-hunting
type
gear
sets.
The pattern in
Fig.
7 runs
from the centre toward the toe and
then back to centre.
The pattern
in
Fig.
8 runs from the tooth centre
toward the heel and then back to
centre. These patterns are not un-
usual for non-hunting gear sets and
are acceptable. The pattern on any
one ring gear tooth was formed by
only one pinion tooth coming into
contact with it. Because of this lim-
ited tooth contact, the non-hunting
pattern can be more erratic than
the hunting pattern and still be ac-
ceptable.
Likewise, the coast pat-
tern on a non-hunting gear set is
usually less uniform tooth to tooth
than it would be on a hunting gear
set
(Fig.
9 ).
Fig.
10 shows a pattern rolled on
another gear set. In this cast:, the
pattern is
fairly
uniform
from
tooth to tooth.
UNACCEPTABLE PATTERN
A non-hunting gear set should be
checked for runout and possible re-
placement if the pattern runs from
the tooth centre towards the toe and
back to centre on some gear teeth
(Fig. 7) while on other teeth of the
same gear, the pattern runs from the
tooth centre toward the heel and
back to centre (Fig. 8).
A hunting gear set showing an
erratic tooth pattern could have one
of the following conditions:
1. Foreign matter between diff-
erential hemisphere gear locating
base and back face of crown wheel.
2. Faulty gear set.
A non-hunting gear set requires a
change in shimming or backlash when
its pattern tends to concentrate
toward the heel or toe, top or bottom
of most teeth (Fig. 1 1 ).
GROUP
4-REAR AXLE
PARTIAL NON-HUNTING
GEAR SET
In a partial non-hunting type gear
set, any one pinion tooth comes into
contact with only part of the ring
gear teeth, but more than one
revolution of the ring gear is required
to make all possible gear tooth com-
binations.
Tooth to tooth pattern uniformity
will usually be in between the hunt-
ing and the non-hunting patterns.
Partial non-hunting gear set patterns
will usually be less uniform than
hunting gear set patterns, but more
uniform than non-hunting gear set
patterns.
SHIM AND BACKLASH
CHANGES
The patterns shown in Fig.
11
are
typical of gear sets that have either
an incorrect backlash or an incorrect
shim adjustment. Since each gear set
rolls a characteristic pattern, the
patterns in Fig.
11
should be con-
sidered as typical only and should be
used as a guide rather than a rigid
standard. The drive pattern is rolled
on the convex side of the tooth, and
the
coast.
pattern is rolled on the
concave s1de.
DRIVELINE VIBRATION
Vehicle vibration and roughness is
often the result of driveline vari-
ations. Driveline disturbance vibra-
tions are usually high frequency
vibrations and are somewhat worse
on acceleration, or rapid deceleration.
The vibration produces a buzzing
feeling, a droning condition or, as
some customers describe, a "pressure
noise on the
eardrums".
It is likely
that the vibration sensation is more
noticeable in the rear seat and over
the driveline, than in any other area
of the car.
Driveline vibrations
frequently
originate from excessive runout of
the driveline components, namely
pinion companion flange, the pinion
itself, driveshaft, slip yoke and
transmission output shaft. Runout
in these components will produce
vibrations due to the fact that the
components will be rotating on a
centre other than the centre of
balance.
Unbalance of one or more of the
driveline components will produce
vibration.
Driveline angles and the amount
of deflection across the universal
joints will also produce similar
vibrations.
LIMITED SLIP AND
TRACTION LOK AXLES
When encountering complaints of
limited slip or Traction Lok cone or
clutch plate
chatter,
the vehicle
should be driven in fairly tight
circles, 5 times clockwise and 5 times
anti-clockwise at approximately 5
m.p.h. to allow lubricant to work in
between the cone friction surfaces or
clutch plates.
If the chatter persists drain the
lubricant, refill the axle with the
specified lubricant and repeat the
foregoing procedure.
Should chatter still be evident dis-
mantling of the differential
for
further inspection and repair will be
necessary.
A whirring sound due to over-
running of the cones in the integral
carrier limited slip differential is no
indication of unit failure.
To test the Limited Slip or
Traction Lok
differentials
for correct
operation proceed as follows:
1. Raise one rear wheel and re-
move the wheel cover, attach Tool
T65K-4204-A at the wheel nuts
(Fig.
13).
2. Place the transmission in neu-
tral.
3. Chock the front wheels.
4. Attach a torque meter of at
least 200
ft.
lbs. capacity to the
torque check tool as in Fig. 13 and
rotate the
axle.
NOTE: The torque required to
rotate the shaft should be at least
40 ft. lbs. for Traction Lok and
50 ft. lbs. for limited slip.
The initial breakaway torque may
be higher than the continuous turn-
ing torque. This is normal.
The axle should turn with reason-
able evenness. However, the torque
may vary up to 40 ft
. lbs.
on Traction
Lok differentials.
If the torque required to continu-
ously rotate the wheel is outside
specification check the differential
for
FIG. 13-
Limited
Slip
or
Traction Lok Differential
-Torque Check on Vehicle
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