1988 PONTIAC FIERO light

REAR AXLE 481-1 5
Fig. 17 Installing Service Shims
left shim and add difference to the
right side. Keep total shim thickness
at a value equal to that obtained in
step b.
NOTICE: Original light drag is caused by weight
of the case against the carrier while additional drag
is caused by side bearing preload.
For convenience in setting backlash and tooth
contact, the preload will not be added until the
final step.
4. Check backlash and tooth pattern as described in
the following section. The bearing caps must be
installed and the bolts torqued to specified torque
(follow assembly sequence below).
5. When backlash and tooth pattern operations are
complete, remove shim packs taking care not to
mix them. Select new shims for each side
.004"
thicker than those removed and install each shim
on its proper side. This additional thickness will
provide proper bearing preload. It will be
necessary to tap the
final shim into place with a
soft hammer and tool
5-25588 (Fig. 17).
1. FRONT PINION
BEARING AND
RACE
2. SPACER
J 351 18-5
3.
SIDE DISCS J 21 777-45
4. THRU BOLT J 21 777-43 5.
SPACER
J 21777-42
6. REAR PINION
BEARING
7. ARBOR
J 23597-1
8. GAGE PLATE
351 18-2
J10003-4B1 -F
Fig. 18 Hypoid Pinion and Bearing Shim Selection
1. Drive front pinion bearing cup in the carrier
(Item a) with tool
5-7817. (Fig. 19).
1-J-8092 DRIVE
NOTICE: Check total rotational torque. Total
torque with differential case preloaded and pinion Fig. 19 Front Pinion Bearing Cup Installation
installed should be 4 to 6 in. lb, over pinion bearing
preload specification. If total rotational torque 2. Fit spacer (item
b) into carrier bore.
does
not- meet this specification, reset the
differential bearing preload spacers as developed in 3. Slide the rear pinion bearing and cap (item f) onto
steps
3 thru 5. the
thru bolt (item d) and rear bearing into axle
housing.
Assemble 4. Install thru bolt (item d) and rear bearing and cap
(item
f) into axle housing.
5. Assemble front bearing cone (item a) and spacer
(item e) onto thru bolt.
Pinion 6. Rotate nut and shaft and increase torque on the Hypoid Pinion and Bearing Shim Selection
nut until a rotational toraue of 1.7 to 2.8 N-m
(15-22 lb. in.) is obtained: Rotate the thru bolt
NOTICE: Select pinion head positioning shim using back
and forth during tightening to ensure
pattern setting kit
J 35118-A. Refer to Fig. 18. correct
seating of bearing.

REAR AXLE 4B-3
Noise which originates in other places cannot be
corrected by adjustment or replacement of parts in the
differential. It should also be remembered that rear
axle gears, like any other mechanical device, are not
absolutely quiet and should be accepted as being
commercially quiet unless some abnormal noise is
present.
To make a systematic check for axle noise under
standard conditions, observe the following:
1. Select a level smooth asphalt road to reduce tire
noise and body drumming.
2. Check rear axle lubricant to assure correct level,
then drive car far enough to thoroughly warm up
rear axle lubricant.
3. Note speed and RPM at which noise occurs. Then
stop car and with automatic transmission in neutral,
run engine slowly up and down through engine speeds, corresponding to car speed at which noise
was most pronounced, to determine if it is caused by
exhaust, muffler roar or other engine conditions.
4. Tire noise changes with different road surfaces,
but rear axle noise does not. Temporarily
inflating all tires to approximately 50 pounds
pressure for
test purposes only will materially
alter noise caused by tires, but will not affect noise
caused by rear axle. Rear axle noise usually stops
when coasting at speeds under 30 miles per hour;
however, tire noise continues, but with lower
tone, as car speed is reduced. Rear axle noise
usually changes when comparing acceleration
and coast, but tire noise remains about the same.
Distinguish between tire noise and rear axle noise
by noting if noise varies with various speeds or
sudden acceleration and deceleration; exhaust
and axle noise show variations under these
conditions while tire noise remains constant and
is more pronounced at speeds of 20 to 30 miles
per hour. Further check for tire noise by driving
car over smooth pavements or dirt roads (not
gravel) with tires at normal pressure. If noise is
caused by tires, it will noticeably change or
disappear and reappear with changes in road
surface.
5. Loose or rough front wheel bearings will cause
noise which may be confused with rear axle
noises; however, front wheel bearing noise does
not change when comparing drive and coast.
Light application of brakes while holding car
speed steady will often cause wheel bearing noise
to diminish, as this takes some weight off the
bearing. Front wheel bearings may be easily
checked for noise by jacking up the wheels and
spinning them, also by shaking wheels to
determine if bearings are loose.
6. Rear suspension rubber bushings and spring
insulators dampen out rear axle noise when
correctly installed. Check to see that no metallic
contact exists between the spring and spring
opening in frame or between upper and lower
control arm bushings and frame or axle housing
brackets.
Metal-to-metal contact at those points
may result in telegraphing road noise and normal axle
noise which would not be objectionable if
dampened by bushings.
AXLE NOISES
Gear Noise
After the noise has been determined as being in
the
axle by following the above appraisal procedure,
the type of axle noise should be determined to aid in
maki~~g repairs if necessary.
Gear noise (whine) is audible from 20 to
55 mph
under four driving conditions:
1. Drive - Acceleration or heavy pull.
2. Road Load - Car driving load or constant speed.
3. Float
- Using
enough throttle to keep the car from
driving the engine
- car slows down gradually but
engine still pulls slightly.
4. Coast
- Throttle closed and car in gear. Gear
noise most frequently has periods where noise is
more prominent, usually 30 to 40 mph and 50 to
55 mph.
Bearing Noise
Bad bearings generally produce more of a rough
growl or grating sound, rather than the whine typical
of gear noise. Bearing noise frequently "wow-wows" at
bearing rpm, indicating a defective pinion or rear axle
case side bearing. This noise could easily be confused
with rear wheel bearing noise. Inspect and replace as
required.
Rear Wheel Bearing Noise
A rough rear wheel bearing produces a noise
which continues with car coasting at low speed and
transmission in neutral. Noise may diminish some by
gentle braking. With rear wheels jacked up, spin rear
wheels by hand while listening at hubs for evidence of
rough (noisy) wheel bearing.
I(noclc At Low Speeds
Low speed knock can be caused by worn
universal joints or a side gear hub counterbore in a case
that has worn oversize. Inspect and replace universal
joint or case and side gear as required.
Baclclash Clunk
Excessive clunk with acceleration and
deceleration is caused by worn differential pinion shaft,
excessive clearance between axle shaft and side gear
splines, excessive clearance between side gear hub and
counterbore in case worn pinion and side gear teeth,
worn thrust washers and excessive drive pinion and
rear gear backlash. Remove worn parts and replace as
required, selecting close fitting parts when possible.
Adjust pinion and ring gear backlash.
REAR AXLE STANDARD AND LIMITED-SLIP
1. Noise is the same in "Drive" or "Coast".
a. Road noise.
b. Tire noise.
c. Front wheel bearing noise.

4B-4 REAR AXLE
d. Incorrect driveline angle.
Noise changes on a different type of road.
a. Road noise.
b. Tire noise.
Noise tone lowers as car speed is lowered.
a. Tire noise.
Similar noise is produced with car standing and
driving.
a. Engine noise.
b. Transmission noise.
Vibration. a. Rough rear wheel bearing.
b. Unbalanced
or damaged propeller shaft.
c. Tire unbalance.
d. Worn
universal joint in propeller shaft.
e. Incorrect driveline angle.
f. Mis-indexed propeller shaft at pinion
flange.
g. Pinion
flange
runout too great.
A knock or click approximately every two
revolutions of the rear wheel.
a. A rear wheel bearing.
Noise most pronounced on turns.
a. Rear
axle side gear and pinion noise.
A continuous low pitch whirring or scraping
noise starting at relatively low speed.
a. Pinion bearing noise.
Drive noise, coast noise or float noise.
a. Ring and
pinion gear noise.
Clunk on acceleration or deceleration.
a. Worn rear
axle pinion shaft in case or side
gear hub counterbore in case worn oversize.
b. Insufficient
lubrication on propeller shaft
slip yoke.
c. Worn U-joints on
propeller shaft. Front or
rear.
Groan in "Forward" or "Reverse".
a. Wrong
or contaminated lube in rear axle.
b. Worn bushings.
Chatter on turns.
a. Wrong
or contaminated lube in rear axle.
b. Clutch
cone worn and/or
spring(s) worn.
Clunk or knock on rough road operation.
a. Excessive end play of axle shafts to
differential cross shaft.
b. Worn bushings.
PRE-REPAIR INVESTIGATION AND TROUBLE
DIAGNOSIS
A careful1 diagnosis of the rear axle prior to
disassembly will often reveal valuable information as to
the extent and type of repairs or adjustments necessary.
Since frequent causes of axle noises are improper
backlash, pinion bearing pre-load, or side bearing
pre-load, or a combination, a few simple adjustments
may be all that are necessary to correct a problem.
Therefore, before removing the rear axle from the
housing, the following checks should be made with the
results recorded and analyzed:
1) Backlash; 2) Total Assembly
Preload; 3) Tooth Contact Pattern Test;
4)
Fluid Level; and 5) Fluid Contamination.
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.
The pinion and ring gear must be completely
assembled, installed and all pre-load and backlash
adjustments completed prior to the start of this method
of pinion depth setting. The following procedure can
be used in place of the gage method of pinion depth
setting.
Gear Tooth Nomenclature
The side of the ring gear tooth which curves
outward, or is 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 the
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 rear axle carrier assembly is disassembled.
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.
Tooth Contact Pattern Test
1. Wipe oil out of carrier and carefully clean each
tooth of ring gear.
2. Use gear marking compound part number
1052351 or equivalent 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.
3. Tighten bearing cap bolts to 75
N.m (55 lb. ft.).
4. Expand
brake shoes using parking brake cables
until a torque of 54 to
70 N-m (40-50 lb. ft.) is
required to turn the pinion.
A test made without loading the gears will not
give a satisfactory pattern. Turn pinion flange
with wrench so that ring gear rotates one full
revolution, then reverse rotation so that ring gear
rotates one revolution in opposite direction.
5. Observe
pattern on ring gear teeth and compare
with Fig. 3.
Effects of Increasing Load on Teeth Contact
Pattern
When "load" on ring and pinion gear is
increased, such as when car is accelerated forward
from standstill or from normal drive, the tooth contact
will tend to spread out and, under very heavy load, will
extend from near toe to near heel on the drive side. The
entire contact also tends to shift toward heel under
increasingly heavier loads and will become somewhat
broader with respect to tops and bottoms of teeth. The
patterns obtained by this tooth contact pattern test
approximate a light load and, for this reason, they will
extend only about halfway.

REAR AXLE 48-5
BRINELLIM
SURFACE INDENTATIONS IN RACEWAY
CAUSED BY ROLLERS EITHER UNDER
IMPACT LOADING OR VIBRATION WHILE
THE BEARING IS NOT ROTATING.
REPLACE BEARING IF ROUGH OR NOISY.
I
CRACKED INNER RACE
RACE CRACKED DUE TO IMPROPER FIT,
COCKING, OR POOR BEARING SEATS.
mOE WEAR
WEAR AROUND OUTSIDE DIAMETER OF
CAGE AND ROLLER POCKETS CAUSEC
BY ABRASIVE MATERIAL
AN0 INEFFICIENT LUBRICATION. CHECK
SEALS AND REPLACE BEARINGS.
SMEARING OF METAL DUE TO SLIPPAGE,
SLIPPAGE CAN BE CAUSED BY POOR
F ITS, LUBRICATION, OVERHEATING,
OVERLOADS OR HANDLING DAMAGE.
REPLACE BEARINGS. CLEAN RELATED
PARTS AND CHECK FOR PROPER FIT
AND LUBRICATION. ABRASIVE
ROLLER
WUR
PAmERN ON RACES AND ROLLERS
CAUSED BY FINE ABRASIVES.
CLEAN ALL PARTS AND HOUSINGS,
CHECK SEALS AND BEARINGS AND
REPLACE IF LEAKING, ROUGH
OR NOISY.
FRETTACE
CORROSION SET UP BY SMALL
RELATIVE MOVEMENT OF PARTS WlTH
NO LUBRICATION.
REPLACE BEARING. CLEAN RELATED
PARTS. CHECK SEALS AND CHECK FOR
PROPER LUBRICATION.
HEAT DISCOLORATION CAN RANGE
FROM FAINT YELLOW TO DARK BLUE
RESULTING FROM OVERLOAD OR
INCORRECT LUBRICANT.
EXCESSIVE
HEAT CAN CAUSE
SOFTENING OF RACES OR ROLLERS.
TO CHECK FOR LOSS OF TEMPER ON
DISCOLORATION CAN RANGE FFmM RACES OR ROLLERS A SIMPLE FILE TEST LIGHT BROWN TO BLACK CAUSED BY MAY BE MADE. A FILE DRAWN OVER A lNCORRECT LUBRICANT OR MOISTURE.
TEMPERED PART
WlLL GRAB AND CUT METAL, WHEREAS. A FILE DRAWN OVER RE-USE BEARINGS IF STAINS CAN BE
A HARD PART WILL GLIDE READILY REMOVED BY LIGHT POLISHING OR IF WITH NO METAL CUTTING NO EVIDENCE OF OVERHEATING IS
OBSERVED.
REPLACE BEARINGS IF OVER
HEATING
DAMAGE IS INDICATED. CHECK SEALS CHECK SEALS AND RELATED PARTS FOR
AND OTHER PARTS. DAMAGE.
J10001-40-F
Fig. 2 Rear Axle Bearing Diagnosis

4B-8 REAR AXLE
GENERAL lNFORMATlON
A universal joint connects the rear end of the
propeller shaft to a pinion flange, having a splined end
which fits over and drives the
hypoid pinion gear. The
housing is attached to the underbody through a center
bearing support. Inside the housing, an extension shaft
is splined to the drive pinion at the rear end, and to the
companion flange at the other end. Two pre-loaded
tapered roller bearings support the
hypoid pinion gear
in the carrier. The inner race of the rear bearing is a
light press fit on the pinion stem. The inner race of the
front bearing combines a light press fit to a close sliding
fit on the pinion flange end of the pinion stem. The
outer race of each bearing is pressed against a shoulder
recessed in the carrier. Tightening the pinion nut
compresses a collapsible spacer which bears against the
inner race of the front bearing and a shoulder on the
pinion stem. This spacer is used to enable accurate
bearing pre-load adjustment and
maintain a pre-load
on both front and rear pinion bearings. Adjustment of the
fore and aft position of the pinion is obtained by
placing
shims between the head of the drive pinion and
the rear pinion bearing.
The rear axle case is of
one-piece construction and is supported in the carrier
by two tapered roller side bearings. These are
pre-loaded by inserting
shims between the bearings and
the carrier. The rear axle case assembly is positioned
for proper ring gear to pinion backlash by varying the
shin1 thickness from side to side. The ring gear is bolted
to the case. Two side gears have splined bores for
driving the axle shafts. They are positioned to turn in
counterbored cavities in the case. The two rear axle
pinions have
smooth bores and are held in position by
a solid pinion cross shaft, mounted and locked in the
rear axle case. All four gears are in
mesh with each
other and because the pinion gears turn freely
on their
shaft, they act as idler gears when the rear wheels are
turning at different speeds. The pinions and side gears
are backed by steel thrust washers.
LIMITED-SLIP REAR AXLE
The operation of the Limited-Slip differential is
the same as the standard differential, except that there
is additional friction provided by the clutches or cones.
Under ordinary driving and cornering conditions, the
clutches or cones slip, allowing the outside wheel to
turn faster than the inner. Under poor traction
conditions, such as ice, snow, or loose gravel under one
driving wheel, the increased friction provided by the clutches
or cones increases the driving torque available
to the wheel with the better traction. The clutches or
cones are spring loaded to provide the increased
driving torque under extremely low traction
conditions.
Most rear axle service repairs can be made with
the rear axle assembly in the car, by raising the rear end
of the car with the rear axle hanging
on the shock
absorbers.
ON-VEHICLE SERVICE
CARRIER COVER AND GASKET
Remove or Disconnect
1. Having a container in place, remove cover bolts
and pry cover loose to drain lubricant.
2. Make sure both gasket sealing surfaces are clean.
Install or Connect
Use sealant
1052366 or cover gasket
only.
1. Torque cover bolts in a crosswise pattern to
insure uniform draw on gasket. Torque
27 N.m
(20 Ib.fr.).
2. Fill with lubricant to a level within 4.5mm (3116")
or filler plug hole. Refer to specifications for correct
lubricant usage and quantity.
Axle Shaft
a Remove or Disconnect
1. Raise car and remove wheel and brake drum.
2. Clean all dirt from area of carrier.
3. Remove bolts and differential carrier cover and
allow lubricant to drain.
4. Remove pinion shaft lock screw and pinion shaft.
1 -PINION SHAFT 2-PINION SHAFT 1
SCREW 520122 48
Fig. 401 Pinion Shaft Lock Bolt
5. Push flanged end of axlc shalt inward to pcrmil
removal of "C" locks, thcn rcmovc axlc shafts
being
careful not to cl;uii~~gc oil scal (Fig. 402).
6. Remove axlc shaft from housing, bcing curcl'ul not
to
damage oil scal.

REAR AXLE 48-1 1
Rear Wheel Bolt
Remove or Disconnect 1.
1. Raise vehicle on hoist allowing axle to hang
freely. 2.
2. Remove
wheel, tire and brake drum.
3. Using Tool J 6627-A press out stud.
Fig. 4 10 Removing Wheel Bolt
REAR AXLE ASSEMBLY
Install or Connect
Fig. 4 11 Installing Wheel Bolt
UNIT REPAIR
Remove or Disconnect
Place new stud in axle flange hole. Slightly start
stud serrations in hole by firmly pressing back of
stud with your hand.
Place a flat washer on the stud and install a lug
nut with flat side first (tapered face outboard).
Tighten on lug nut drawing stud into flange until
stud head is bottomed on back side of flange.
Remove lug nut.
Reinstall brake drum (or rotor and caliper),
wheel and tire.
Lower vehicle and remove from hoist.
It is not necessary to remove the rear axle
assembly for any normal repairs. However, if the
housing is damaged, the rear axle assembly may be
removed and installed using the following procedure.
Hoist car and support at frame. Hoist must
remain under rear axle housing.
Disconnect both shock absorbers.
Remove bolt securing left side of track bar to
axle.
Remove brake line junction block bolt at axle
housing, then disconnect brake lines at junction
block.
Lower rear axle assembly on hoist and remove
springs.
Remove rear wheels and drums.
Remove rear axle cover and drain lube.
Remove axle shafts.
Disconnect brake lines from axle housing clips.
Remove brake backing plates.
Disconnect lower control arms from axle
housing.
Disconnect torque arm at axle.
Mark propeller shaft and companion flange and
disconnect shaft and support out of the way.
Remove rear axle housing.
Install or Connect
Install rear axle housing.
Install propeller shaft aligning marks made at
time of removal.
Connect torque arm to axle.
Connect lower control arms to axle.
Install brake backing plates.
Connect brake lines to axle housing.
Install axle shafts.
Install axle housing cover.
Install rear wheels and drums.
Raise axle and install springs.
Install brake line to junction block, then mount
junction block on axle housing.
Install track bar to axle.
Connect shock absorbers.
Fill axle and bleed brake system.
Remove supports and lower car.
Disassembly of Rear Axle Assembly
Before attempting any service procedures the
technician must know what type rear axle is to be
serviced. Refer to chart (Rear Axle Codes And
Identification) to identify codes, ring gear size, and
ratios. Remember that all ring gear bolts have L.H.
threads.
Most rear axle service repairs can be made by
supporting the car by the frame with the axle housing
supported and lowered to its lowest travel. On some

48-16 REAR AXLE
4.32mm (.170") SERVICE WACER
TOTAL THICKNESS OF TOTAL THICKNESS OF
BOTH PROD. SHIMS SERVICE SHIMS TO BE
REMOVED USED AS A STARTING POINT
Fig. 6 13 Shim Thickness
makes contact with the carrier bore so as to
obtain a correct reading. The point just before
additional drag begins is correct feeler gage
thickness. Rotate case while using feeler gage to
assure an even reading.
The original light drag is caused by weight of the
case against the carrier while additional drag is
caused by side bearing pre-load. By starting with
a thin feeler gage, a sense of "feel" is obtained so
that the beginning of pre-load can be recognized
to obtain Zero clearance. It will be necessary to
work case in and out and to the left in order to
insert the feeler gage.
6. Remove left bearing cap and shim from carrier.
The total shim pack needed (with no pre-load on
side bearings) is the feeler gage reading found in
Step
5 plus thickness of shims installed in Step 4.
7. Select two shims of approximately equal size
whose total thickness is equal to the value
obtained in Step
5. These shims will be installed
between each side bearing race and service spacer
when the case is installed in the carrier. The
object of Step 7 is to obtain the equivalent of a
"slip fit" of the case in the carrier. For
convenience in setting backlash, the pre-load will
not be added until the final step.
8. If the pinion is in position, install the ring gear,
then proceed to Rear Axle Backlash Adjustment.
DRIVE PINION
Install or Connect
1.
Install NEW collapsible spacer on pinion and
position assembly in carrier. Lubricate pinion
bearings with Rear Axle Lubricant before
installing pinion.
NOTICE: There are two types of collapsible
spacers. The conventional collapsible spacer is
used on the
7-1/2" and 8-1/2" axles. The new
inverted type is used only on the
7-5/8" axle.
Fig. 6 14 Installing Differential Adjusting Shims
COLLAPSIBLE DRIVE SPACER PINION I
Fig. 61 5 Collapsible Spacer on Drive Pinion
2.
Hold forward on pinion in case assembly.
3. Install front bearing on pinion and drive bearing
on pinion shaft until seated in race.
4. Position pinion oil seal in carrier. Install seal.
5. Coat lips of pinion oil seal and seal surface of
pinion flange with Lubricant No. 1050169 or
equivalent. Install pinion flange on pinion by
tapping with a soft hammer until a few pinion
threads project through flange.
6. Install pinion washer and nut. Hold pinion
flange, while intermittently rotating pinion to
seat pinion bearings. Tighten pinion flange nut
until end play begins to be taken up.
When no further end play is detectable and when
holder will no longer pivot freely as pinion is
rotated, pre-load specifications are being

REAR AXLE 48-1 7
approached. No further tightening should be
attempted until the pre-load has been checked.
7. Check pre-load by using an inch pound torque
wrench.
NOTICE: After pre-load has been checked, final
tightening should be done very carefully. For
example, if when checking, pre-load was found to
be 0.6
N-m (5 lbs. in.), any additional tightening
of the pinion nut can add many additional pound
inch of torque. Therefore, the pinion nut should be
further tightened only a little at a time and the
pre-load should be checked after each slight
amount of tightening. Exceeding pre-load
specifications will compress the collapsible spacer
too far and require the installation of a new
collapsible spacer.
While observing the preceeding note, carefully set
pre-load at 2.7 to 3.6
N-m (24 to 32 1b.in.) on new
bearings or 1.0 to 1.4
N m (8 to 12 1b.in.) on used
bearings.
8. Rotate pinion several times to assure that
bearings have been seated. Check pre-load again.
If pre-load has been reduced by rotating pinion,
reset pre-load to specifications.
Rear Axle Backlash Adjustment
1. Install rear axle case into carrier, using shims as
determined by the side bearing pre-load
adjustment.
2. Rotate rear axle case several times to seat
bearings, then mount dial indicator. Use a small
button on the indicator stem so that contact can
be made near heel end of tooth. Set dial indicator
so that stem is in line as nearly as possible with
gear rotation perpendicular to tooth angle for
accurate backlash reading.
3. Check backlash at three or four points around
ring gear. Lash must not vary over
.05mm (.002")
around ring gear. Pinion must be held stationary
when checking backlash. If variation is over
.05mm (.002") check for burrs, uneven bolting
conditions or distorted case flange and make
corrections as necessary.
4. Backlash at the point of minimum lash should be
between .13 and
.23mm (.005" and ,009") for all
new gears.
5. If backlash is not within specifications, correct by
increasing thickness of one shim and decreasing
thickness of other shim the same amount. This
will maintain correct rear axle side bearing
pre-load.
For each
.03mm (.001") change in backlash
desired, transfer
.05mm (.002") in shim
thickness. To decrease backlash
.03mm (.00lU),
decrease thickness of right shim .05mm (.002")
and increase thickness of left shim .05mm (.
002 "). To increase backlash .05mm (.002 ")
increase thickness of right shim .10mm (.004")
and decrease thickness of left shim .10mm (.
004"). 6.
When backlash is correctly adjusted, remove both
bearing caps and both shim packs.
Keep packs in their respective position, right or
left side.
Select a shim
.10mm (.004") thicker than the one
removed from the left side, then insert left side
shim pack between the spacer and the left bearing
race. Loosely install bearing cap.
7. Select a shim
.10mm (.004") thicker than the one
removed from right side and insert between the
spacer and the right bearing race. It will be
necessary to drive the right shim into position
(Fig. 614).
8. Torque to 75 Nem (55 1b.ft.).
9. Recheck backlash
and correct if necessary.
10. Install axles (See Rear Axle Installation).
11.
Use sealant 1052366 or cover gasket
only.
Install cover and torque cover bolts to 27
N-m (20 1b.ft.).
12. Fill rear axle to proper level with the specified
lubricant. Refer to specifications.
LIMITED SLIP REAR AXLE (GONE TYPE)
The cone-type limited-slip differential has several
definite operating characteristics. An understanding of
these characteristics is necessary as an aid to diagnosis.
The clutch energizing force comes from the
thrust side of the gears. Consequently, a free spinning
wheel may not have enough resistance to drive torque
to apply the clutch cones. If this occurs, apply the
parking brake a few notches which will provide enough
resistance to energize the clutch cones.
Energizing the clutch cones is independent of
acceleration; therefore, a very slow application of the
throttle on starting is recommended to provide
maximum traction by preventing "break away" of
either rear wheel.
Improper operation is generally indicated by cone
slippage or grabbing. Sometimes this produces a
chatter or whirring sound. However, these sounds do
not always indicate failure as they could be produced
from a lack of proper lubrication. For example, under
certain conditions where one wheel is on
a very slippery
surface and the other on dry pavement, wheel spin can
occur if over acceleration is attempted. Continued
spinning may cause audible noise, such as a whirring
sound, due to the cones lacking sufficient lubricant.
This does not necessarily indicate failure of the unit.
During regular operation (straight ahead driving)
when both wheels rotate at equal speeds, there is an
approximately equal driving force delivered to each
wheel. When cornering, the inside wheel delivers extra
driving force causing slippage in both clutch cones.
Consequently, the operational life of the limited slip
unit is dependent upon equal rotation of both wheels
during straight ahead operation. If wheel rotation for
both rear wheels is not equal during straight ahead
operation, the limited-slip unit will constantly be
functioning as if the vehicle were cornering. This will
impose constant slippage on the clutch cones and will
eventually lead to abnormal wear on the clutch cones.
Therefore, it is important that there be no excessive
differences in the rear wheel tire sizes, air pressures, or