differential FORD MUSTANG 2003 Owner's Manual

WARNING: Do not balance the wheels and tires while they are mounted on the vehicle.
Possible tire disintegration/differential failure could result, causing personal injury/extensive
component damage. Use an off- vehicle wheel and tire balancer only.
Most vibration in the rear end is caused by tires or driveline angle.
Vibration is a concern with modern, high- mileage tires if they are not "true" both radially and laterally.
They are more susceptible to vibration around the limits of radial and lateral runout of the tire and
wheel assembly. They also require more accurate balancing. Wheel and tire runout checks, truing and
balancing are normally done before axle inspection. Refer to Section 204 - 04 .
Driveline Angle
Driveline angularity is the angular relationship between the engine crankshaft (6303), the driveshaft,
and the rear axle pinion. Factors determining driveline angularity include ride height, rear spring, and
engine mounts.
Driveline Angle
An incorrect driveline (pinion) angle can often be detected by the driving condition in which the
vibration occurs.
zA vibration during coastdown from 72 to 56 km/h (45 to 35 mph) is often caused by an
excessive U-joint angle at the axle (pinion nose downward).
z A vibration during acceleration, from 56 to 72 km/h (35 to 45 mph) may indicate an excessive U- joint angle at the axle (pinion nose upward). Item Description
1 Bottom of the frame
2 Engine crankshaft centerline
3 Engine angle
4 Driveshaft and coupling shaft centerline
5 Driveshaft and coupling shaft angle
6 Rear axle pinion centerline
7 Axle pinion angle Klj . 4 ba
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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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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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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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DESCRIPTION AND OPERATION
Driveshaft
NOTE:
All driveshaft assemblies are balanced. If undercoating the vehicle, protect the driveshaft to
prevent overspray of any undercoating material.
The driveshaft has the following features:
zA tubular shaft used to transfer engine torque from the transmission output shaft to the
differential in the rear axle housing, which transmits torque through the axle shafts to the drive
SECTION 205-
01: Driveshaft 2003 Mustang Workshop Manual Item Part Number Description
1 N800594-S100 Bolt (4 req'd)
2 4635 Universal joint (U-
joint) 3 4602 Driveshaft
4 — Grease seal (part of 4635)
5 — Needle bearings (part of 4635)
6 — Bearing cup (part of 4635)
7 — Thrust washer (part of 4635)
8 — Spider (part of 4635)
9 4841 Driveshaft slip yoke
10 — Snap ring (4 req'd)
(part of 4635)
11 4782 Driveshaft centering socket yoke
12 4851 Rear axle universal joint flange Klj . 1 ba
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SPECIFICATIONS
a
In- vehicle repair refill capacities are determined by filling the rear axle with the specified lubricant to
6.4- 14.3- mm (1/4- 9/16-in) below the bottom of the fill hole.
SECTION 205-
02A: Rear Drive Axle/Differential — Ford 7.5-Inch Ring
Gear 2003 Mustang Workshop
Manual General Specifications
Item Specification
Lubes and Sealers
SAE 80W-
90 Premium Rear Axle Lubricant XY-
80W90- QL WSP-
M2C197- A Premium Long-
Life Grease XG -1-C ESA-
M1C75- B Rust Penetrant and Inhibitor F2AZ-19A501-
A ESR-
M99C56- A High Temperature Nickel Anti-
Sieze Lubricant
F6AZ- 9L494- AA ESE-
M124A- A Clear Silicone Rubber F7AZ-
19554-CA ESB-
M4G92- A Threadlock and Sealer EOAZ-19554-
AA WSK-
M2G351- A5 Lubricant Fill Level Checks
Approximate axle fill capacity
a 1.54-1.66-
liters (3.25-3.50- pints)
6.4-14.3- mm (1/4-9/16- in) below the bottom of
the fill hole Clearance, Tolerance and Adjustments
Maximum ring gear back face runout 0.102 mm (0.004 in)
Maximum differential case runout 0.076 mm (0.003 in)
Differential side gear thrust washer thickness 0.762 mm -
0.813 mm (0.030 in - 0.032 in) Differential pinion gear thrust washer thickness 0.762 mm -
0.813 mm (0.030 in - 0.032 in) Maximum axle shaft end play 0.762 mm (0.030 in)
Ring gear backlash 0.203 mm-
0.381 mm
(0.008 in- 0.015 in)
[(0.305 mm- 0.381 mm
(0.012 in- 0.015 in) preferred] Variation between teeth maximum backlash 0.102 mm (0.004 in)
Pinion flange runout 0.25 mm (0.010 in) T.I.R.
Torque Specifications Description Nm lb-
ft lb-
in Bolt retaining the differential pinion shaft to the differential case 30 22 —
Bolt retaining the driveshaft yoke to the pinion flange 112 83 —
Bolt retaining the differential housing cover to the differential housing 44 32 —
Oil filler plug 30 22 —
Pinion bearing preload (used pinion bearings) 0.9-
1.5 — 8-
14 Pinion bearing preload (new pinion bearings) 1.8-
3.3 — 16-
29 Adapter for 205-
S127 2.2 — 20 Klj . 1 ba
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Bolt retaining the bearing cap to the differential case 105 77 —
Bolt retaining the ring gear to the differential case 105 77 — Klj . 2 ba
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DESCRIPTION AND OPERATION
Rear Drive Axle and Differential
SECTION 205-
02A: Rear Drive Axle/Differential — Ford 7.5-Inch Ring
Gear 2003 Mustang Workshop
Manual Item Part Number Description
1 4236 Differential side gear
2 4228 Differential side gear thrust washer
3 4221 Differential bearing Klj . 1 ba
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4 4222 Differential bearing cup
5 4067 Differential bearing shim
6 4216 Rear axle differential gear case bolt
7 4204 Differential case
8 — Ring gear (part of 4209)
9 — Bearing cap (part of 4010)
10 4010 Rear axle housing
11 373098-
S Filler plug
12 4662 Collapsible spacer
13 4670 Rear axle drive pinion shaft oil slinger
14 4676 Rear axle drive pinion seal
15 4851 Pinion flange
16 389546-S100 Pinion nut
17 4621 Differential pinion bearing
18 2C026 Rear brake disc
19 — Axle shaft flange (part of 4234)
20 2C189 Rear brake anti-
lock sensor indicator 21 2552 Rear disc brake caliper
22 N601951-S2 Bolt
23 N804361-S100 Clip
24 — Bolt
25 2C190 Rear brake anti-
lock sensor 26 2C101 Left hand rear disc brake adapter
27 2C100 Right hand rear disc brake adapter
28 N8015163-S190 Caliper anchor bolt
29 2C028 Rear wheel brake disc shield
30 N602726-S2 Bolt (3 req'd)
31 4616 Differential drive pinion bearing cup
32 4628 Rear axle pinion bearing cup
33 4630 Differential pinion bearing
34 — Drive pinion gear
(part of 4209)
35 4663 Drive pinion bearing adjustment shim
36 — Bolt (part of 4010)
37 4241 Differential pinion shaft lock bolt
38 4211 Differential pinion shaft
39 4N237 U-
washer 40 383548 Bolt
41 — Rear axle identification tag
42 4033 Differential housing cover
43 4230 Differential pinion thrust washer
44 4215 Differential pinion gear Klj . 2 ba
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