
down several times. Always release the bumper in
the down position.Set the front end alignment to
specifications while the vehicle is in its NOR-
MALLY LOADED CONDITION.
Camber and caster angle adjustments involve
changing the position of the upper suspension arm
pivot bar (Fig. 3). Refer to the Alignment Specifica-
tion Chart for the correct setting.
CASTER:Move the rear position of the pivot bar
in or out. This will change the caster angle signifi-
cantly and camber angle only slightly. To retain cam-
ber move the forward pivot very slightly in the
opposite direction.
NOTE: For example, to increase a positive caster
angle, move the rear position of the pivot bar
inward (toward the engine). Move the front of pivot
bar outward (away from the engine) slightly until
the original camber angle is obtained.CAMBER:Move the forward position of the pivot
bar in or out. This will change the camber angle sig-
nificantly and caster angle only slightly. The camber
angle should be adjusted as close as possible to the
preferred service specification. After adjustment
is made tighten pivot bar nuts to specifications.
TOE POSITION:The wheel toe position adjust-
ment should be the final adjustment.
(1) Start the engine and turn wheels both ways
before straightening the wheels. Center and secure
the steering wheel and turn off engine.
(2) Loosen the tie rod adjustment sleeve clamp
bolts/nuts.
NOTE: Each front wheel should be adjusted for
one-half of the total toe position specification. This
will ensure the steering wheel will be centered
when the wheels are positioned straight-ahead.
(3) Adjust the wheel toe position by turning the tie
rod adjustment sleeves as necessary.
STANDARD PROCEDURES - CASTER
CORRECTION MEASUREMENT
NOTE: To determine the correct caster alignment
angle for Cab-Chassis vehicles the following proce-
dure must be performed.
NOTE: 4x2 11000 GVW has a solid front axle and
uses a 4x4 frame.
(1) Take a height measurement to the center of the
front gauge hole in the frame. Take another measure-
ment to the center of the rear spring hanger bolt
(Fig. 4). Take these measurements on both sides of
the vehicle.
(2) Subtract the front measurement from the rear
measurement and use the average between the right
and left side. Use this number (caster correlation
valve) with the Corrected Caster Chart to obtain the
preferred caster angle.
Fig. 3 Caster Camber Adjustment Location
1 - PIVOT BAR
2 - UPPER SUSPENSION ARM
3 - SUSPENSION ARM FRAME MOUNT
4 - ADJUSTMENT SLOTS
BR/BEWHEEL ALIGNMENT 2 - 3
WHEEL ALIGNMENT (Continued)

CORRECTED CASTER CHART-CAB CHASSIS
Caster
Correlation
Value
(inches)4x2 8800
lb. GVW
134.7 in.
wheel
base4x4 8800
lb. GVW
4x2 & 4x4
11000 lb.
GVW
134.7 &
138.7 in.
wheel
base4x2 & 4x4
11000 lb.
GVW 162.7
in. wheel
base
Caster61
deg.Caster61
deg.Caster61
deg.
þ5.00 4.27É 3.77É 3.81É
þ4.75 4.39É 3.89É 3.91É
þ4.50 4.51É 4.01É 4.01É
þ4.25 4.64É 4.14É 4.11É
þ4.00 4.76É 4.26É 4.21É
þ3.75 4.88É 4.38É 4.31É
þ3.50 5.00É 4.50É 4.41É
þ3.25 5.12É 4.62É 4.51É
þ3.00 5.25É 4.75É 4.61É
þ2.75 5.37É 4.87É 4.71É
þ2.50 5.49É 4.99É 4.81É
þ2.25 5.61É 5.11É 4.91É
þ2.00 5.74É 5.24É 5.01É
þ1.75 5.86É 5.36É 5.11É
þ1.50 5.98É 5.48É 5.21É
þ1.25 6.10É 5.60É 5.31É
þ1.00 6.23É 5.73É 5.41É
þ0.75 6.33É 5.83É 5.51É
þ0.50 6.47É 5.97É 5.61É
þ0.25 6.59É 6.09É 5.71É
0.00 6.71É 6.21É 5.81É
STANDARD PROCEDURES - ALIGNMENT
LINK/COIL SUSPENSION
Before each alignment reading the vehicle should
be jounced (rear first, then front). Grasp each
bumper at the center and jounce the vehicle up and
down several times. Always release the bumper in
the down position.Set the front end alignment to
specifications while the vehicle is in its NOR-
MALLY LOADED CONDITION.
CAMBER:The wheel camber angle is preset and
is not adjustable.
CASTER:Check the caster of the front axle for
correct angle. Be sure the axle is not bent or twisted.Road test the vehicle and make left and right turn.
Observe the steering wheel return-to-center position.
Low caster will cause poor steering wheel returnabil-
ity.
Caster can be adjusted by rotating the cams on the
lower suspension arm (Fig. 5). (Refer to 2 - SUSPEN-
SION/WHEEL ALIGNMENT - STANDARD PROCE-
DURE).
TOE POSITION:The wheel toe position adjust-
ment should be the final adjustment.
(1) Start the engine and turn wheels both ways
before straightening the wheels. Center and Secure
the steering wheel and turn off engine.
(2) Loosen the adjustment sleeve clamp bolts.
(3) Adjust the right wheel toe position with the
drag link. Turn the sleeve until the right wheel is at
the correct TOE-IN position. Position clamp bolts to
their original position and tighten to specifications.
Make sure the toe setting does not change dur-
ing clamp tightening.
(4) Adjust left wheel toe position with tie rod at
left knuckle. Turn the sleeve until the left wheel is at
the correct TOE-IN position. Position clamp bolts to
their original position and tighten to specifications.
Make sure the toe setting does not change dur-
ing clamp tightening.
(5) Verify the right toe setting.
Fig. 5 Adjustment Cam
1 - ADJUSTMENT CAM
2 - AXLE BRACKET
3 - BRACKET REINFORCEMENT
4 - LOWER SUSPENSION ARM
BR/BEWHEEL ALIGNMENT 2 - 5
WHEEL ALIGNMENT (Continued)

DRIVELINE VIBRATION
Drive Condition Possible Cause Correction
Propeller Shaft Noise 1) Undercoating or other foreign
material on shaft.1) Clean exterior of shaft and wash
with solvent.
2) Loose U-joint clamp screws. 2) Install new clamps and screws
and tighten to proper torque.
3) Loose or bent U-joint yoke or
excessive runout.3) Install new yoke.
4) Incorrect driveline angularity. 4) Measure and correct driveline
angles.
5) Rear spring center bolt not in
seat.5) Loosen spring u-bolts and seat
center bolt.
6) Worn U-joint bearings. 6) Install new U-joint.
7) Propeller shaft damaged or out
of balance.7) Installl new propeller shaft.
8) Broken rear spring. 8) Install new rear spring.
9) Excessive runout or unbalanced
condition.9) Re-index propeller shaft, test,
and evaluate.
10) Excessive drive pinion gear
shaft runout.10) Re-index propeller shaft and
evaluate.
11) Excessive axle yoke deflection. 11) Inspect and replace yoke if
necessary.
12) Excessive transfer case runout. 12) Inspect and repair as necessary.
Universal Joint Noise 1) Loose U-joint clamp screws. 1) Install new clamps and screws
and tighten to proper torque.
2) Lack of lubrication. 2) Replace as U-joints as
necessary.
BALANCE
NOTE: Removing and re-indexing the propeller
shaft 180É relative to the yoke may eliminate some
vibrations.
If propeller shaft is suspected of being unbalanced,
it can be verified with the following procedure:
(1) Raise the vehicle.
(2) Clean all the foreign material from the propel-
ler shaft and the universal joints.
(3) Inspect the propeller shaft for missing balance
weights, broken welds, and bent areas.If the pro-
peller shaft is bent, it must be replaced.
(4) Inspect the universal joints to ensure that they
are not worn, are properly installed, and are cor-
rectly aligned with the shaft.
(5) Check the universal joint clamp screws torque.
(6) Remove the wheels and tires. Install the wheel
lug nuts to retain the brake drums or rotors.
(7) Mark and number the shaft six inches from the
yoke end at four positions 90É apart.(8) Run and accelerate the vehicle until vibration
occurs. Note the intensity and speed the vibration
occurred. Stop the engine.
(9) Install a screw clamp at position 1 (Fig. 6).
(10) Start the engine and re-check for vibration. If
there is little or no change in vibration, move the
clamp to one of the other three positions. Repeat the
vibration test.
(11) If there is no difference in vibration at the
other positions, the source of the vibration may not
be propeller shaft.
(12) If the vibration decreased, install a second
clamp (Fig. 7) and repeat the test.
(13) If the additional clamp causes an additional
vibration, separate the clamps (1/2 inch above and
below the mark). Repeat the vibration test (Fig. 8).
(14) Increase distance between the clamp screws
and repeat the test until the amount of vibration is
at the lowest level. Bend the slack end of the clamps
so the screws will not loosen.
3 - 4 PROPELLER SHAFTBR/BE
PROPELLER SHAFT (Continued)

mate and side gears. The side gears are splined to
the axle shafts.
During straight-ahead driving, the differential pin-
ion gears do not rotate on the pinion mate shaft. This
occurs because input torque applied to the gears is
divided and distributed equally between the two side
gears. As a result, the pinion gears revolve with the
pinion mate shaft but do not rotate around it (Fig. 2).When turning corners, the outside wheel must
travel a greater distance than the inside wheel to
complete a turn. The difference must be compensated
for to prevent the tires from scuffing and skidding
through turns. To accomplish this, the differential
allows the axle shafts to turn at unequal speeds (Fig.
3). In this instance, the input torque applied to the
pinion gears is not divided equally. The pinion gears
now rotate around the pinion mate shaft in opposite
directions. This allows the side gear and axle shaft
attached to the outside wheel to rotate at a faster
speed.
DIAGNOSIS AND TESTING - AXLE
GEAR NOISE
Axle gear noise can be caused by insufficient lubri-
cant, incorrect backlash, tooth contact, worn/damaged
gears or the carrier housing not having the proper
offset and squareness.
Gear noise usually happens at a specific speed
range. The noise can also occur during a specific type
of driving condition. These conditions are accelera-
tion, deceleration, coast, or constant load.
When road testing, first warm-up the axle fluid by
driving the vehicle at least 5 miles and then acceler-
ate the vehicle to the speed range where the noise is
the greatest. Shift out-of-gear and coast through the
peak-noise range. If the noise stops or changes
greatly:
²Check for insufficient lubricant.
²Incorrect ring gear backlash.
²Gear damage.
Differential side gears and pinions can be checked
by turning the vehicle. They usually do not cause
noise during straight-ahead driving when the gears
are unloaded. The side gears are loaded during vehi-
Fig. 1 216 FBI Differential Cover
1 - FILL PLUG
2 - IDENTIFICATION TAG
3 - DIFFERENTIAL COVER
Fig. 2 Differential Operation-Straight Ahead Driving
1 - IN STRAIGHT AHEAD DRIVING EACH WHEEL ROTATES AT
100% OF CASE SPEED
2 - PINION GEAR
3 - SIDE GEAR
4 - PINION GEARS ROTATE WITH CASE
Fig. 3 Differential Operation-On Turns
1 - PINION GEARS ROTATE ON PINION SHAFT
BR/BEFRONT AXLE - 216FBI 3 - 13
FRONT AXLE - 216FBI (Continued)

cle turns. A worn pinion mate shaft can also cause a
snapping or a knocking noise.
BEARING NOISE
The axle shaft, differential and pinion bearings can
all produce noise when worn or damaged. Bearing
noise can be either a whining, or a growling sound.
Pinion bearings have a constant-pitch noise. This
noise changes only with vehicle speed. Pinion bearing
noise will be higher pitched because it rotates at a
faster rate. Drive the vehicle and load the differen-
tial. If bearing noise occurs, the rear pinion bearing
is the source of the noise. If the bearing noise is
heard during a coast, the front pinion bearing is the
source.
Worn or damaged differential bearings usually pro-
duce a low pitch noise. Differential bearing noise is
similar to pinion bearing noise. The pitch of differen-
tial bearing noise is also constant and varies only
with vehicle speed.
Axle shaft bearings produce noise and vibration
when worn or damaged. The noise generally changes
when the bearings are loaded. Road test the vehicle.
Turn the vehicle sharply to the left and to the right.
This will load the bearings and change the noise
level. Where axle bearing damage is slight, the noise
is usually not noticeable at speeds above 30 mph.
LOW SPEED KNOCK
Low speed knock is generally caused by a worn
U-joint or by worn side-gear thrust washers. A worn
pinion shaft bore will also cause low speed knock.
VIBRATION
Vibration at the rear of the vehicle is usually
caused by:
²Damaged drive shaft.²Missing drive shaft balance weight(s).
²Worn or out of balance wheels.
²Loose wheel lug nuts.
²Worn U-joint(s).
²Loose/broken springs.
²Damaged axle shaft bearing(s).
²Loose pinion gear nut.
²Excessive pinion yoke run out.
²Bent axle shaft(s).
Check for loose or damaged front end components
or engine/transmission mounts. These components
can contribute to what appears to be a rear end
vibration. Do not overlook engine accessories, brack-
ets and drive belts.
All driveline components should be examined
before starting any repair.
(Refer to 22 - TIRES/WHEELS - DIAGNOSIS AND
TESTING)
DRIVELINE SNAP
A snap or clunk noise when the vehicle is shifted
into gear (or the clutch engaged) can be caused by:
²High engine idle speed.
²Transmission shift operation.
²Loose engine/transmission/transfer case mounts.
²Worn U-joints.
²Loose spring mounts.
²Loose pinion gear nut and yoke.
²Excessive ring gear backlash.
²Excessive side gear to case clearance.
The source of a snap or a clunk noise can be deter-
mined with the assistance of a helper. Raise the vehi-
cle on a hoist with the wheels free to rotate. Instruct
the helper to shift the transmission into gear. Listen
for the noise, a mechanics stethoscope is helpful in
isolating the source of a noise.
3 - 14 FRONT AXLE - 216FBIBR/BE
FRONT AXLE - 216FBI (Continued)

mate and side gears. The side gears are splined to
the axle shafts.
During straight-ahead driving, the differential pin-
ion gears do not rotate on the pinion mate shaft. This
occurs because input torque applied to the gears is
divided and distributed equally between the two side
gears. As a result, the pinion gears revolve with the
pinion mate shaft but do not rotate around it (Fig. 2).When turning corners, the outside wheel must
travel a greater distance than the inside wheel to
complete a turn. The difference must be compensated
for to prevent the tires from scuffing and skidding
through turns. To accomplish this, the differential
allows the axle shafts to turn at unequal speeds (Fig.
3). In this instance, the input torque applied to the
pinion gears is not divided equally. The pinion gears
now rotate around the pinion mate shaft in opposite
directions. This allows the side gear and axle shaft
attached to the outside wheel to rotate at a faster
speed.
DIAGNOSIS AND TESTING - AXLE
GEAR NOISE
Axle gear noise can be caused by insufficient lubri-
cant, incorrect backlash, tooth contact, worn/damaged
gears or the carrier housing not having the proper
offset and squareness.
Gear noise usually happens at a specific speed
range. The noise can also occur during a specific type
of driving condition. These conditions are accelera-
tion, deceleration, coast, or constant load.
When road testing, first warm-up the axle fluid by
driving the vehicle at least 5 miles and then acceler-
ate the vehicle to the speed range where the noise is
the greatest. Shift out-of-gear and coast through the
peak-noise range. If the noise stops or changes
greatly:
²Check for insufficient lubricant.
²Incorrect ring gear backlash.
²Gear damage.
Differential side gears and pinions can be checked
by turning the vehicle. They usually do not cause
noise during straight-ahead driving when the gears
are unloaded. The side gears are loaded during vehi-
Fig. 1 248 FBI Differential Cover
1 - FILL PLUG
2 - MODEL NUMBER
3 - RATIO TAG
4 - DIFFERENTIAL COVER
Fig. 2 Differential Operation-Straight Ahead Driving
1 - IN STRAIGHT AHEAD DRIVING EACH WHEEL ROTATES AT
100% OF CASE SPEED
2 - PINION GEAR
3 - SIDE GEAR
4 - PINION GEARS ROTATE WITH CASE
Fig. 3 Differential Operation-On Turns
1 - PINION GEARS ROTATE ON PINION SHAFT
3 - 46 FRONT AXLE - 248FBIBR/BE
FRONT AXLE - 248FBI (Continued)

cle turns. A worn pinion mate shaft can also cause a
snapping or a knocking noise.
BEARING NOISE
The axle shaft, differential and pinion bearings can
all produce noise when worn or damaged. Bearing
noise can be either a whining, or a growling sound.
Pinion bearings have a constant-pitch noise. This
noise changes only with vehicle speed. Pinion bearing
noise will be higher pitched because it rotates at a
faster rate. Drive the vehicle and load the differen-
tial. If bearing noise occurs, the rear pinion bearing
is the source of the noise. If the bearing noise is
heard during a coast, the front pinion bearing is the
source.
Worn or damaged differential bearings usually pro-
duce a low pitch noise. Differential bearing noise is
similar to pinion bearing noise. The pitch of differen-
tial bearing noise is also constant and varies only
with vehicle speed.
Axle shaft bearings produce noise and vibration
when worn or damaged. The noise generally changes
when the bearings are loaded. Road test the vehicle.
Turn the vehicle sharply to the left and to the right.
This will load the bearings and change the noise
level. Where axle bearing damage is slight, the noise
is usually not noticeable at speeds above 30 mph.
LOW SPEED KNOCK
Low speed knock is generally caused by a worn
U-joint or by worn side-gear thrust washers. A worn
pinion shaft bore will also cause low speed knock.
VIBRATION
Vibration at the rear of the vehicle is usually
caused by:
²Damaged drive shaft.²Missing drive shaft balance weight(s).
²Worn or out of balance wheels.
²Loose wheel lug nuts.
²Worn U-joint(s).
²Loose/broken springs.
²Damaged axle shaft bearing(s).
²Loose pinion gear nut.
²Excessive pinion yoke run out.
²Bent axle shaft(s).
Check for loose or damaged front end components
or engine/transmission mounts. These components
can contribute to what appears to be a rear end
vibration. Do not overlook engine accessories, brack-
ets and drive belts.
All driveline components should be examined
before starting any repair.
(Refer to 22 - TIRES/WHEELS - DIAGNOSIS AND
TESTING)
DRIVELINE SNAP
A snap or clunk noise when the vehicle is shifted
into gear (or the clutch engaged) can be caused by:
²High engine idle speed.
²Transmission shift operation.
²Loose engine/transmission/transfer case mounts.
²Worn U-joints.
²Loose spring mounts.
²Loose pinion gear nut and yoke.
²Excessive ring gear backlash.
²Excessive side gear to case clearance.
The source of a snap or a clunk noise can be deter-
mined with the assistance of a helper. Raise the vehi-
cle on a hoist with the wheels free to rotate. Instruct
the helper to shift the transmission into gear. Listen
for the noise, a mechanics stethoscope is helpful in
isolating the source of a noise.
BR/BEFRONT AXLE - 248FBI 3 - 47
FRONT AXLE - 248FBI (Continued)

When road testing, first warm-up the axle fluid by
driving the vehicle at least 5 miles and then acceler-
ate the vehicle to the speed range where the noise is
the greatest. Shift out-of-gear and coast through the
peak-noise range. If the noise stops or changes
greatly:
²Check for insufficient lubricant.
²Incorrect ring gear backlash.
²Gear damage.
Differential side gears and pinions can be checked
by turning the vehicle. They usually do not cause
noise during straight-ahead driving when the gears
are unloaded. The side gears are loaded during vehi-
cle turns. A worn pinion shaft can also cause a snap-
ping or a knocking noise.
BEARING NOISE
The axle shaft, differential and pinion bearings can
all produce noise when worn or damaged. Bearing
noise can be either a whining, or a growling sound.
Pinion bearings have a constant-pitch noise. This
noise changes only with vehicle speed. Pinion bearing
noise will be higher pitched because it rotates at a
faster rate. Drive the vehicle and load the differen-
tial. If bearing noise occurs, the rear pinion bearing
is the source of the noise. If the bearing noise is
heard during a coast, the front pinion bearing is the
source.
Worn or damaged differential bearings usually pro-
duce a low pitch noise. Differential bearing noise is
similar to pinion bearing noise. The pitch of differen-
tial bearing noise is also constant and varies only
with vehicle speed.
Axle shaft bearings produce noise and vibration
when worn or damaged. The noise generally changes
when the bearings are loaded. Road test the vehicle.
Turn the vehicle sharply to the left and to the right.
This will load the bearings and change the noise
level. Where axle bearing damage is slight, the noise
is usually not noticeable at speeds above 30 mph.
LOW SPEED KNOCK
Low speed knock is generally caused by a worn
U-joint or by worn side±gear thrust washers. A worn
pinion shaft bore will also cause low speed knock.
VIBRATION
Vibration at the rear of the vehicle is usually
caused by a:
²Damaged drive shaft.
²Missing drive shaft balance weight(s).
²Worn or out-of-balance wheels.
²Loose wheel lug nuts.
²Worn U-joint(s).
²Loose/broken springs.
²Damaged axle shaft bearing(s).
²Loose pinion gear nut.
²Excessive pinion yoke run out.
²Bent axle shaft(s).
Check for loose or damaged front-end components
or engine/transmission mounts. These components
can contribute to what appears to be a rearend vibra-
tion. Do not overlook engine accessories, brackets
and drive belts.
All driveline components should be examined
before starting any repair.
(Refer to 22 - TIRES/WHEELS - DIAGNOSIS AND
TESTING)
DRIVELINE SNAP
A snap or clunk noise when the vehicle is shifted
into gear (or the clutch engaged), can be caused by:
²High engine idle speed.
²Transmission shift operation.
²Loose engine/transmission/transfer case mounts.
²Worn U-joints.
²Loose spring mounts.
²Loose pinion gear nut and yoke.
²Excessive ring gear backlash.
²Excessive side gear to case clearance.
The source of a snap or a clunk noise can be deter-
mined with the assistance of a helper. Raise the vehi-
cle on a hoist with the wheels free to rotate. Instruct
the helper to shift the transmission into gear. Listen
for the noise, a mechanics stethoscope is helpful in
isolating the source of a noise.
BR/BEREAR AXLE - 9 1/4 3 - 81
REAR AXLE - 9 1/4 (Continued)