FORD MUSTANG 2003 Workshop Manual

NOTE:
A low-pitched rumble normally associated with a worn/damaged wheel bearing can also be
caused by tires.
A wheel bearing noise can be mistaken for a pinion bearing noise. Check the wheel bearing for a
spalled cup, and spalled/damaged rollers. Check the wheel bearing for rotating smoothness and end
play. Install a new wheel bearing if any of these concerns are detected.
If the wheel bearing is damaged, the roller surface on the axle shaft may also be damaged. Install a
new axle shaft if any damage is detected.
Chuckle
Chuckle that occurs on the coast driving phase is usually caused by excessive clearance between the
differential gear hub and the differential case bore.
Damage to a gear tooth on the coast side can cause a noise identical to a chuckle. A very small tooth
nick or ridge on the edge of a tooth can cause the noise.
Clean the gear tooth nick or ridge with a small grinding wheel. If the damaged area is larger than 3.2
mm (1/8 inch), install a new gearset.
To check the ring gear and pinion, remove as much lubricant as possible from the gears with clean
solvent. Wipe the gears dry or blow them dry with compressed air. Look for scored or damaged teeth.
Also look for cracks or other damage.
If either gear is scored or damaged badly, install a new ring gear and pinion. Klj . 7 ba
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If metal has broken loose, the axle housing must be cleaned to remove particles that will cause
damage. At this time, any other new parts in the axle housing must also be installed, if necessary.
Knock
Knock, which can occur on all driving phases, has several causes including damaged teeth or gearset.
In most cases, one of the following conditions will occur:
1. A gear tooth damaged on the drive side is a common cause of the knock. This can usually be corrected by grinding the damaged area. Klj . 8 ba
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2.
NOTE: Measure the end play with a Dial Indicator with Bracketry and not by feel.
Knock is also caused by excessive end play in the axle shafts. Up to 0.762 mm (0.030 inch) is
allowed in semi- float axles. The frequency of the knock will be less because the axle shaft
speed is slower than the driveshaft.
Clunk
Clunk is a metallic noise heard when the automatic transmission is engaged in REVERSE or DRIVE.
The noise may also occur when throttle is applied or released. It is caused by backlash somewhere in
the driveline or loose suspension components; it is felt or heard in the axle. Refer to Total Backlash
Check in this section.
Additionally, clunk may be heard upon initial drive- away. This occurs as engine torque shifts vehicle
weight, forcing changes in driveline angles, preventing the driveshaft slip- yoke from sliding on the
output shaft. To correct for this condition, lubricate the slip- yoke splines.
Total Backlash Check 1. Raise and support the vehicle. Refer to Section 100 - 02 .
2. Remove the driveshaft. Refer to Section 205 - 01 .
3. Install the special tool. zClamp a rigid bar or pipe to the tool. Clamp the other end of the bar or pipe to the frame
or a body member in order to prevent movement of the rear axle pinion flange.
4. Lower the vehicle so that one rear wheel is resting on a wheel chock to prevent it from turning. The other rear wheel will be used to measure total rear axle backlash.
5. Rotate the free wheel slowly, by hand, until the feeling of driving the rear axle is encountered. Place a mark on the side of the tire, 305 mm (12 inches) from the center of the wheel, with a Klj . 9 ba
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crayon or chalk.
6. While holding the crayon or chalk against the tire, rotate the wheel slowly in the opposite direction until the feeling of driving the rear axle is encountered again.
7. Measure the length of the crayon or chalk mark on the tire. zIf the length of the mark is 25.4 mm (1 inch) or less, the rear axle backlash is within
allowable limits.
z If the chalk mark is greater than 25.4 mm (1 inch), check for these conditions:
„Elongation of the differential pinion shaft and holes in the differential case (4204).
„ Missing differential pinion thrust washer (4230) or differential side gear thrust
washer (4228).
„ Galling of the differential pinion shaft (4211) and bore.
„ Excessive ring gear and pinion backlash. Follow the procedure for the type of rear
axle to check backlash.
Axle Shaft Bearing Noise
Axle bearing shaft noise is similar to gear noise and differential pinion bearing whine. Axle shaft
bearing noise will usually distinguish itself from gear noise by occurring in all driving modes (drive,
coast, and float), and will persist with the transmission in NEUTRAL while the vehicle is moving at the
speed in which the concern is occurring. If the vehicle makes this noise, remove the suspect axle
shaft, install a new bearing and a new axle seal. Re- evaluate the vehicle for noise before removing any
internal components.
Bearing Rumble
Bearing rumble sounds like marbles being tumbled. This condition is usually caused by a
worn/damaged wheel bearing. The lower pitch is because the wheel bearing turns at only about one-
third of the driveshaft speed. Wheel bearing noise also may be high- pitched, similar to gear noise, but
will be evident in all four driving modes.
Symptom Chart
Symptom Chart Condition
Possible Sources Action
z Traction- Lok®
does not work in
snow, mud or on
ice z
Differential. zCARRY OUT the Traction-
Lok® Differential Operation
Check in this section. REPAIR
as necessary. REFER to
Section 205 - 02A or
Section 205 - 02B .
z Lubricant leaking
from the pinion
seal, axle shaft oil
seals z
Vent.
z Damage in the
seal contact area
or damaged or
worn seal. z
CLEAN the axle housing vent.
z INSTALL a new seal if
damage is found.
z Differential side
gears/pinion
gears are scored z
Insufficient
lubrication. z
INSTALL new gears. REFER
to Section 205 - 02A or
Section 205 - 02B . FILL the axle to
specification.
z Incorrect or
contaminated z
INSTALL new gears. REFER
to Section 205 - 02A or
Section Klj . 10 ba
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Component Tests
Driveline Vibration
An analysis of driveline vibration can also be conducted using the Vibration Analyzer; follow the
manufacturer's directions.
Driveline vibration exhibits a higher frequency and lower amplitude than does high-
speed shake.
Driveline vibration is directly related to the speed of the vehicle and is usually noticed at various speed
ranges. Driveline vibration can be perceived as a tremor in the floorpan or is heard as a rumble, hum,
or boom. Driveline vibration can exist in all drive modes, but may exhibit different symptoms depending
upon whether the vehicle is accelerating, decelerating, floating, or coasting. Check the driveline angles
if the vibration is particularly noticeable during acceleration or deceleration, especially at lower speeds.
Driveline vibration can be duplicated by supporting the axle upon a hoist or upon jack stands, though
the brakes may need to be applied lightly in order to simulate road resistance.
1. Raise the vehicle promptly after road testing. Use a twin- post hoist or jack stands to prevent tire
flat- spotting. Engage the drivetrain and accelerate to the observed road test speed to verify the lubricant type.
205 - 02B . CLEAN and
REFILL the axle to
specification.
z Axle overheating zLubricant level too
low. z
CHECK the lubricant level.
FILL the axle to specification.
z Incorrect or
contaminated
lubricant type. z
INSPECT the axle for
damage. REPAIR as
necessary. CLEAN and
REFILL the axle to
specification.
z Bearing preload
adjusted too tight. z
CHECK the ring and pinion for
damage. INSPECT the ring
and pinion wear pattern.
ADJUST the preload as
necessary.
z Excessive gear
wear. z
INSPECT all the axle gears
for wear or damage. INSTALL
new components as
necessary.
z Incorrect ring gear
backlash. z
INSPECT the ring gear for
scoring. INSPECT the ring
and pinion wear pattern.
ADJUST the ring gear
backlash as necessary.
z Broken gear teeth
on the ring gear
or pinion z
Overloading the
vehicle. z
INSTALL a new ring and
pinion. REFER to Section 205 - 02A or
Section 205 - 02B .
z Axle shaft broken zOverloading the
vehicle. z
INSTALL a new axle shaft.
REFER to Section 205 - 02A or
Section 205 - 02B .
z Misaligned axle
shaft tube. z
INSPECT the axle for
damage. CHECK axle shaft
tube alignment. INSTALL a
new axle shaft. REFER to
Section 205 - 02A or
Section 205 - 02B . Klj . 11 ba
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presence of the vibration. If the vibration is not evident, check the non-
driving wheels with a
wheel balancer to rule out imbalance as a possible cause. If required, balance the non- driving
wheels and repeat the road test. If the vibration is still evident, proceed to Step 2.
2. Mark the relative position of the drive wheels to the wheel nuts. Remove the wheels. Install all the nuts in the reversed position and repeat the road speed acceleration. If the vibration is gone,
refer to the tire and wheel runout procedure in Section 204 - 04 . If the vibration persists, proceed
to Step 3.
3. Inspect the driveshaft for signs of physical damage, missing balance weight, undercoating, incorrect seating, wear and binding universal joints. Clean the driveshaft and install new
universal joints or a new driveshaft if damaged. Check the index marks (paint spots) on the rear
of the driveshaft and pinion flange. If these marks are more than one- quarter turn apart,
disconnect the driveshaft and re- index to align the marks as closely as possible. After any
corrections are made, recheck for vibration at the road test speed. If the vibration is gone,
reinstall the wheels and road test. If the vibration persists, proceed to Step 4.
4. Raise the vehicle on a hoist and remove the wheels. Rotate the driveshaft by turning the axle and measure the runout at the front, the center, and the rear of the driveshaft with the indicator.
If the runout exceeds 0.89 mm (0.035 inch) at the front or center, a new driveshaft must be
installed. If the front and center are within this limit, but the rear runout is not, mark the rear
runout high point and proceed to Step 5. If the runout is within the limits at all points, proceed to
Step 7.
5. NOTE: Check the U-joints during re- indexing. If a U-joint feels stiff or gritty, install new U- joints.
Scribe alignment marks on the driveshaft and the pinion flange. Disconnect the driveshaft,
rotate it one-half turn, and reconnect it. Circular pinion flanges can be turned in one- quarter
increments to fine tune the runout condition. Check the runout at the rear of the driveshaft. If it is
still over 0.89 mm (0.035 inch), mark the high point and proceed to Step 6. If the runout is no
longer excessive, check for vibration at the road test speed. If vibration is still present, re- index
the driveshaft slip yoke on the transmission output shaft one- half turn and road test the vehicle.
If the vibration persists, proceed to Step 7.
6. Excessive driveshaft runout may originate in the driveshaft itself or in the pinion flange. To determine which, compare the two high points marked in Steps 4 and 5. If the marks are close
together, within about 25 mm (1 inch), a new shaft must be installed and the vehicle road
tested. Klj . 12 ba
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If the marks are on opposite sides of the driveshaft, the yoke or pinion flange is responsible for the
vibration.
When installing a new pinion flange, the driveshaft runout must not exceed 0.89 mm (0.035 inch).
When runout is within limits, recheck for vibration at road speed. If vibration persists, balance the
driveshaft.
7. To balance the driveshaft, install one or two hose clamps on the driveshaft, near the rear. Position of the hose clamp head(s) can be determined by trial- and-error.
8. Mark the rear of the driveshaft into four approximately equal sectors and number the marks 1 through 4. Install a hose clamp on the driveshaft with its head at position No. 1.
Check for vibration at road speed. Recheck with the clamp at each of the other positions to find the
position that shows minimum vibration. If two adjacent positions show equal improvement, position the
clamp head between them. 9. If the vibration persists, add a second clamp at the same position and recheck for vibration. Klj . 13 ba
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If no improvement is noted, rotate the clamps in opposite directions, equal distances from the best
position determined in Step 8. Separate the clamp heads about 13 mm (1/2 inch) and recheck for
vibration at the road speed.
Repeat the process with increasing separation until the best combination is found or the vibration is
reduced to an acceptable level.
10. Install the wheels and road test (vibration noticeable on the hoist may not be evident during the road test). If the vibration is still not acceptable, install a new axle driveline vibration damper
first, if so equipped. If the vibration is still not acceptable, refer to Section 205 - 02A or
Section 205 - 02B for differential case and ring gear runout checks.
Driveshaft Vibrates 1. Road test the vehicle to determine the critical vibration points. Note the road speed, the engine RPM, and the shift lever positions at which the vibration occurs.
2. Stop the vehicle, place the transmission lever in neutral and run the engine through the critical speed ranges determined in Step 1.
3. If no vibration is felt, balance the driveshaft. Refer to Driveline Vibration in this section.
Traction- Lok® Differential Operation Check
A Traction-Lok® differential can be checked for correct operation without removing it from the rear axle
housing.
WARNING: A vehicle equipped with a Traction- Lok® differential will always have both
wheels driving. If only one wheel is raised off the floor and the rear axle is driven by the engine, the wheel on the floor could drive the vehicle off the stand or jack. Be sure both rear wheels are Klj . 14 ba
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off the floor.
With the engine off, raise only one rear wheel. Install the special tool on the wheel nuts.
Use a torque wrench with a capacity of at least 271 Nm (200 lb-
ft) to rotate the axle shaft. Be sure that
the transmission is in NEUTRAL, and that one rear wheel is on the floor while the other rear wheel is
raised off the floor. The breakaway torque required to start rotation must be at least 27 Nm (20 lb- ft).
The initial breakaway torque may be higher than the continuous turning torque.
The axle shaft must turn with even pressure throughout the check without slipping or binding. If the
torque reading is less than specified, check the differential case. Refer to Section 205 - 02A or
Section 205 - 02B .
Traction- Lok® Differential Check Road Test
1. Place one wheel on a dry surface and the other wheel on ice, mud or snow.
2. Gradually open the throttle to obtain maximum traction prior to break away. The ability to move the vehicle demonstrates correct operation of a Traction- Lok® rear axle assembly.
3. When starting with one wheel on an excessively slippery surface, a slight application of the parking brake may be necessary to help energize the Traction- Lok® feature of the differential.
Release the brake when traction is established. Use light throttle on starting to provide
maximum traction.
4. If, with unequal traction, both wheels slip, the limited slip rear axle has done all it can possibly do.
5. In extreme cases of differences in traction, the wheel with the least traction may spin after the Traction-Lok® has transferred as much torque as possible to the non- slipping wheel. Klj . 15 ba
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Companion Flange Runout Check
CAUTION: Pinion bearing preload must be reset if the pinion nut has been loosened or
removed for pinion flange reindexing or installation.
1. Raise the vehicle on a twin- post hoist that supports the rear axle. Refer to Section 100 - 02 .
2. Remove the driveshaft. Refer to Section 205 - 01 .
3. Check the pinion flange for damage.
4. Position the Companion Flange Runout Gauge on the pinion flange.
5. Position the special tools on the pinion flange.
6. Align the holes on the clamp plate with the holes in the pinion flange and install the bolts. Snug the bolts evenly. Item Part Number Description
1 — Pilot (part of 205-
319 [T92L-4851-B]) 2 354845 Pinion nut
3 205-
319 (T92L-4851- B) Companion flange runout gauge
4 — Bolts (2 Req'd)
(Part of 205-
320 [T92L-4851- C]) 5 205-320 Clamp plate (T92L-4851-
C) 6 4851 Pinion flange Klj . 16 ba
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