Pontiac tempest 1968 Service Manual page 146

S T A N D A R D D I F F E R E N T I A L
4A-23
F i g . 4A-45 Checking Ring G e a r to Pinion Backlash
2. With pinion locked to carrier, check gear lash
at 3 or 4 points around ring gear. Lash must not
vary over .002" around ring gear. If variation is
over .002", check for burrs, uneven bolting condi­
tions or distorted case flange and make corrections
as necessary.
3. Gear lash, at the point of minimum lash, should
be .005" to .009" for all new gears. If original gear
set having a wear pattern is being reinstalled, origi­
nal gear lash should be maintained with ± .001".
4. If gear backlash is not within specifications,
correct by increasing thickness of one differential
shim and decreasing thickness of other shim the
same amount. In this way, correct differential bear­
ing preload will be maintained. Shift .002" in shim
thickness for each .001" change in backlash desired.
If backlash is .001" too much, decrease thickness of
right shim .002" and increase thickness of left shim
.002". If backlash is .002" too little, increase thick­
ness of right shim .004" and decrease thickness of
left shim .004".
5. When backlash is adjusted to specifications,
tighten bearing cap bolts to 70 lb. ft. torque.
6. Check tooth contact pattern with red lead test.
NOTE: It may be necessary to readjust the back­
lash to obtain the correct tooth contact pattern.
On high mileage gear sets where a definite wear
pattern has been established, it may be necessary
to exceed . 009" backlash to obtain the desired tooth
contact. It is important, however, not to exceed
. 009" backlash on new gear sets.
If readjusting the backlash doesn't give the cor­
rect tooth contact pattern, the pinion depth must be
readjusted.
7. When correct tooth contact pattern is obtained,
install cover with new gasket on housing. DO NOT
USE GREASE TO RETAIN GASKET. Insert two
upper cover bolts carefully through cover and gasket.
Be sure gasket is flat and not twisted between cover
and housing. Be sure all cover bolts pass through
gasket holes. Torque to 25 ft. lbs.
NOTE: See page 4A-8 for replacement of axle
shaft assemblies.
OIL LEAKS
It is difficult to determine the source of some oil
leaks. Even after the point of leakage has been
determined, it is hard to tell whether the oil is
leaking past the lip of the seal or past the O.D. of
the seal. Therefore, it is a good idea to make sure
the leak is stopped by using a nonhardening sealing
compound around the O.D. of the new seal.
SPECIFICATIONS
REAR AXLE
Type . . .
0
.
0
. Semi-Floating
Type of Drive Modified Hotchkiss
Drive - Final . . . . Hypoid Gear
Lubricant Capacity . . Pontiac-72 oz. or 4 1/2 pints
Tempest or Firebird-48 oz. or 3 pints
Lubricant Multi-purpose Hypoid
Gear Lubricant
Lubricant Level Bottom of Filler Plug Hole
RING AND PINION GEAR
Backlash . . .005" - .009"
Ring gear run-out maximum. . . . , .002"
Ratios . . .
0
See Fig. 4A-4A for Pontiac.
See Fig. 4A-4B for Tempest.
See Fig. 4A-4C for Firebird.
Pinion Bearing Preload (with Ring Gear)
New Bearings (New Seal) 25 lb. in.
Old Bearings (New Seal) 17 lb. in.
Side Bearing Preload Slip Fit Plus .008"