differential FORD MUSTANG 2003 User Guide

z
Tooth contact pattern shown on the drive side of the gear teeth.
z The high contact pattern indicates that the drive pinion is not installed deep enough into the
carrier.
z The differential ring gear backlash is correct, a thinner drive pinion shim is needed. A decrease
will move the drive pinion toward the differential ring gear.
9. A high, thin contact pattern that is worn toward the toe. z Tooth contact pattern shown on the drive side of the gear teeth.
z The drive pinion depth is correct. Increase the differential ring gear backlash.
10. A contact pattern that is worn in the center of the differential ring gear tooth toward the heel. z Tooth contact pattern shown on the drive side of the gear teeth.
z The low contact pattern indicates that the drive pinion is installed too deep into the carrier.
z The differential ring gear backlash is correct. A thicker drive pinion shim is needed.
11. A contact pattern that is worn at the top of the differential ring gear tooth toward the heel. Klj . 66 ba
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z
Tooth contact pattern shown on the drive side of the gear teeth.
z The pinion gear depth is correct. Decrease the differential ring gear backlash.
Tire Wear Patterns and frequency calculations Tire Wear Chart Klj . 67 ba
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SPECIFICATIONS
SECTION 204-
02: Rear Suspension 2003 Mustang Workshop Manual Torque Specifications
Description Nm lb-
ft lb-
in Mustang
Rear shock absorber (upper attachment) 40 30 —
Rear shock absorber (lower attachment) 80 59 —
Shock absorber clevis bracket-to-
axle nut 108 80 —
Upper arm-
to-frame bolt 97 72 —
Upper arm-
to-axle bolt 111 82 —
Lower arm-
to-body attachment bolt 150 111 —
Lower arm-
to-axle bolt 150 111 —
Stabilizer bar-
to-lower arm bolt 55 41 —
Parking brake cable bracket 55 41 —
Axle damper front bolt 90 66 —
Axle damper rear nut 90 66 —
Axle damper bracket-
to-frame bolt 80 59 —
Pinion bumper mount-
to-body bolts 14 10 —
Bracket assembly-
to-differential housing bolt 48 35 —
Wheel nuts 129 95 —
Cobra
Subframe-to-
body bolts 103 76 —
Subframe-to-
rear bracket bolts 103 76 —
Subframe rear bracket-
to-body bolts 80 59 —
Shock absorber-
to-lower arm and bushing bolts 133 98 —
Shock absorber-
to-body nuts 40 30 —
Upper arm and bushing-
to-subframe nuts 90 66 —
Upper arm and bushing-
to-knuckle nut 90 66 —
Lower arm and bushing-
to-subframe bolts 250 184 —
Lower arm and bushing-
to-knuckle nut 115 85 —
Toe link-
to-subframe nut 48 35 —
Toe link-
to-knuckle nut 48 35 —
Stabilizer bar bracket bolt 55 41 —
Stabilizer bar link nuts 48 35 —
Rear axle differential rear insulator-
to-axle housing bolts 103 76 —
Rear brake disc dust shield-
to-knuckle bolts 10 — 89
Brake line-
to-rear brake caliper bolt 40 30 —
Parking brake cable bracket-
to-lower arm and bushing bolt 15 11 —
ABS sensor bolt 23 17 — Klj . 1 ba
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Item Part
Number Description
1 18125 Rear shock absorber
2 — Rear axle driveline vibration damper
3 5A649 Rear lower suspension arm and bushing (common
LH and RH)
4 5560 Rear spring
5 4731 Rear axle bumper bracket
6 4905 Rear axle differential carrier bumper and bracket
7 5A772 Rear stabilizer bar
8 5500 Rear upper suspension arm and bushing
(common LH and RH) Klj . 2 ba
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REMOVAL AND INSTALLATION
Upper Arm
Removal
CAUTION: Suspension fasteners are critical parts because they affect performance of vital
components and systems and their failure can result in major service expense. A new part with
the same part number must be installed if installation becomes necessary. If substitution is
necessary, the part must be of the same finish and property class. Torque values must be used
as specified during reassembly to make sure of correct retention of these parts.
1. Mark the rear shock absorber (18125) relative to the protective sleeve with the vehicle in a static, level ground position (curb height).
2. Raise the vehicle on a hoist. For additional information, refer to Section 100 - 02 .
3. Support the differential housing with a jack stand.
4. Disconnect the upper arm and bushing (5500) from the axle. 1. Remove and discard the nut and bolt.
2. Disconnect the arm and bushing from the axle.
5. Remove the upper arm and bushing from the mounting bracket. 1. Remove and discard the nut and bolt.
2. Remove the arm and bushing.
SECTION 204-
02: Rear Suspension 2003 Mustang Workshop Manual Klj . 1 ba
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4. Remove the bolt and the parking brake cable bracket. Discard the bolt.
Vehicles equipped with a 4.6L 2V engine 5. Remove the stabilizer bar (5A772). For additional information, refer to Stabilizer Bar in this
section.
All vehicles 6. Support the differential housing with a jack stand.
7. Position the special tool 014- 00942 under the rear lower suspension arm and bushing- to-axle
pivot bolt.
8. Remove and discard the pivot bolt and nut.
9. Remove the spring (5560). 1. Slowly lower the arm with the special tool 014- 00942.
2. Remove the rear spring and the rear spring insulators (5536). Installation Klj . 2 ba
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DIAGNOSIS AND TESTING
Wheels And Tires
Inspection and Verification
WARNING: A vehicle equipped with a Traction- Lok® differential will always have both
wheels driving. If, while the vehicle is being serviced, only one wheel is raised off the ground
and the rear axle is driven by the engine, the wheel on the ground could drive the vehicle off
the stand or jack. Be sure both rear wheels are off the ground.
WARNING: Never run the engine with one wheel off the ground, for example, when
changing a tire. The wheel(s) resting on the ground could cause the vehicle to move.
WARNING: Do not balance the wheels and tires while they are mounted on the vehicle.
Possible tire disintegration or differential failure could result, causing personal injury and
extensive component damage. Use off- vehicle wheel and tire balancer only.
Be sure to follow the warnings when carrying out inspection and verification.
Road Test
Verify the customer concern by carrying out a road test on a smooth road. If any vibrations are
apparent, refer to Section 100 - 04 .
To maximize tire performance, inspect for signs of incorrect inflation and uneven wear, which may
indicate a need for balancing, rotation, or front suspension alignment.
Correct tire pressure and driving techniques have an important influence on tire life. Heavy cornering,
excessively rapid acceleration and unnecessary sharp braking increases tire wear.
Replacement tires must follow the recommended:
ztire sizes.
z speed rating.
z load range.
z tire construction type.
Use of any other tire size or type can seriously affect:
zride.
z handling.
z speedometer/odometer calibration.
z vehicle ground clearance.
z tire clearance between the body and chassis.
SECTION 204-
04: Wheels and Tires 2003 Mustang Workshop Manual Klj . 1 ba
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REMOVAL AND INSTALLATION
Wheel And Tire
Removal
1. CAUTION: Do not use heat to loosen a seized wheel nut (1012). Heat can damage
the wheel and wheel bearings.
NOTE: To avoid damage or scratching to the center cap, place facing up when removed.
Loosen the wheel nuts. 1. NOTE: To avoid wheel damage, do not twist wrench when removing center cap.
Remove the center cap, if equipped.
2. Loosen, but do not remove, the wheel nuts.
2. CAUTION: Never use the differential housing as a lifting point.
Raise the vehicle until the tire clears the ground. For additional information, refer to Section 100 - 02 .
3. CAUTION: Do not use heat to loosen a seized wheel because heat can shorten the
life of the wheel and damage the wheel bearings. If the wheel cannot be removed by
hand, use a wheel puller to remove the seized wheel.
Remove the wheel and tire assembly.
zRemove the wheel nuts.
z Remove the wheel and tire.
SECTION 204-
04: Wheels and Tires 2003 Mustang Workshop Manual Klj . 1 ba
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Inspection and Verification
Certain axle noise or vibration symptoms are also common to the engine, transmission, wheel
bearings, tires, and other parts of the vehicle. For this reason, be sure that the cause of the trouble is
in the axle before disassembling, adjusting or repairing the axle. Refer to
Section 100 - 04 .
Certain driveshaft vibration symptoms are common to the front engine accessory drive (FEAD), the
engine, transmission or tires. Be sure the cause of the concern is the driveshaft before repairing or
installing a new driveshaft. Refer to Section 100 - 04 .
Certain symptoms may be caused by Traction- Lok® differentials (4026). Check the vehicle certification
label and axle identification tag to determine the type of differential. Refer to Section 100 - 01 .
Noise Acceptability
NOTE: A gear-driven unit will produce a certain amount of noise. Some noise is acceptable and
audible at certain speeds or under various driving conditions such as a newly paved blacktop road.
Slight noise is not detrimental to the operation of the axle and is considered normal.
With the Traction- Lok® differential axle, slight chatter noise on slow turns after extended highway
driving is considered acceptable and has no detrimental effect on the locking axle function.
Universal Joint (U- Joint) Inspection
Place the vehicle on a frame hoist and rotate the driveshaft (4602) by hand. Check for rough operation
or seized U- joints. Install a new U- joint if it shows signs of seizure, excessive wear, or incorrect
seating. Refer to Section 205 - 01 .
Analysis of Leakage
Clean up the leaking area enough to identify the exact source. An axle leak can be caused by the
following. zAxle lubricant level is too high.
z Worn or damaged axle shaft seals or differential seals.
z Differential housing is cracked.
z Flange yoke seat is worn or damaged.
z Pinion flange is scored or damaged.
z Axle cover is not sealed.
z Vent is plugged. Klj . 2 ba
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Repair the axle as necessary. Make sure the axle lubricant is at the correct level. Refer to
Specifications in this section.
Axle Vent
NOTE:
If a plugged vent cannot be cleared, install a new one.
A plugged vent will cause excessive seal lip wear due to internal pressure buildup. If a leak occurs,
check the vent. Make sure the vent hose is not kinked. Remove the hose from the vent nipple and
clear the hose of any foreign material. While the hose is removed, pass a length of mechanics wire in
and out of the vent to clean it. Connect the hose when done.
Flange Yoke Seal
Leaks at the axle drive pinion seal originate for the following reasons:
zSeal was not correctly installed.
z Poor quality seal journal surface.
Any damage to the seal bore (dings, dents, gouges, or other imperfections) will distort the seal casing
and allow leakage past the outer edge of the axle drive pinion seal.
The axle drive pinion seal can be torn, cut, or gouged if it is not installed carefully. The spring that
holds the axle drive pinion seal against the pinion flange may be knocked out and allow leakage past
the lip.
The rubber lips can occasionally become hard (like plastic) with cracks at the oil lip contact point. The
contact point on the pinion flange may blacken, indicating excessive heat. Marks, nicks, gouges, or
rough surface texture on the seal journal of the pinion flange will also cause leaks.
When a seal leak occurs, install a new seal and check the vent and the vent hose to make sure they
are clean and free of foreign material.
Axle Shaft Seals
Axle shaft oil seals are susceptible to the same kinds of damage as axle drive pinion seals if incorrectly
installed. The seal bore must be clean and the lip handled carefully to avoid cutting or tearing it. The
axle shaft journal surface must be free of nicks, gouges, and rough surface texture.
Differential Seals
Refer to Section 205 - 02A or
Section 205 - 02B .
Analysis of Vibration 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
off the floor.
Few vibration conditions are caused by the rear axle. On a vibration concern, follow the diagnosis
procedure in Section 100 - 04 unless there is a good reason to suspect the axle.
Tires Klj . 3 ba
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