Pontiac tempest 1968 Service Manual page 134

S T A N D A R D DIFFERENTIAL
4A-11
9. Connect rear brake hose to top of housing and
bend tabs over brake lines on housing.
10. Fill rear axle with specified gear lubricant.
11. Bleed rear brakes as outlined in Section 5.
REMOVE DIFFERENTIAL
1. With rear wheels off floor, rotate rear wheels
and tap brake backing plates with a soft hammer to
ensure that brakes are free.
2. Remove both axle shafts.
3. Remove U-bolts which hold rear universal joint
to companion flange. Use a heavy rubber band or
tape to hold bearings onto journal to prevent loss of
bearing rollers when joint is disconnected If tie wire
has been removed (Fig. 4A-5).
4. Thoroughly clean differential housing cover and
surrounding area of axle housing to avoid dirt enter­
ing housing or falling on the gears.
5. Drain oil by loosening all cover attaching bolts
and then break loose cover about 1/8".
6 . Allow oil to drain thoroughly, then remove at­
taching bolts and cover from housing.
PRE-REPAIR INVESTIGATION
A close examination of the differential prior to
disassembly will often reveal valuable Information
as to the extent and type of repairs or adjustments
necessary. The information thus gained, coupled
with the report of malfunctioning, will provide a
basis for determining the degree of disassembly
required. Since the frequent causes of axle noise
are improper backlash or side bearing preload, or
both, a few simple adjustments may be all that is
necessary to correct a problem.
Therefore, before removing the differential from
the housing, the following checks should be made,
with the results recorded and analyzed:
A. Backlash (See Page 4A-22).
B. Pinion Bearing Preload (See Page 4A-20).
C. Red Lead Test (See Page 4A-11).
Use care at all times to keep dirt and other foreign
matter, such as grinder dust, soot or sand away
from differential to prevent possibility of subsequent
failure.
GEAR TOOTH NOMENCLATURE
The side of the ring gear tooth which curves out­
ward, or i s convex, is referred to as the drive
side. The concave side is the coast side. The end
of the tooth nearest center of ring gear is referred
to as the toe end. The end of the tooth farthest
away from center is the heel end. Toe end of tooth
is smaller than heel end. It is very important that
tooth contact be tested before the differential carrier
assembly is disassembled and before it is installed.
Allowable variations in the carrier or pinion rear
bearing may cause the pinion to be too far away
from, or close to, the ring gear. Thus, the tooth
contact must be tested and corrected, if necessary,
or the gears may be noisy.
R E D L E A D T E S T
1. Mix a small amount of powdered red lead (avail­
able from paint manufacturers and suppliers) with a
drop of engine oil and apply this mixture sparingly
to all ring gear teeth, using a medium stiff brush.
When properly used, the area of pinion tooth contact
will be visible when hand load is applied.
2. Tighten bearing cap bolts to 70 lb. ft. torque,
tapping heads of bolt intermittently while tightening,
to ensure proper seating of caps and sufficient
tightness.
3. Insert crank (Fig. 4A-15) in companion flange
and, while turning, apply pressure to back side of
ring gear by hand (a leather glove can be used).
A test made without loading the gears will not give
a satisfactory pattern. Turn companion flange with
crank so that ring gear rotates one full revolution,
then reverse rotation so that ring gear rotates one
revolution in opposite direction. Excessive turning of
ring gear may indicate good tooth pattern because
one or two teeth are making proper contact.
6 (APPRO)^-
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e
I . D . H.D. WASHER
WELD S E C U R E L Y
F i g . 4 A - 1 5 D i f f e r e n t i a l Cranking Tool
NOTE: The crank in Fig. 4A-15 may be easily
made as follows: