2003 FORD MUSTANG engine

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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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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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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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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7. To check the engine angle, rotate the driveshaft so that the slip yoke ear is parallel to the floor.
Remove the U- joint snap ring, then install the special tool. Check and record the engine angle
reading.
zIf the angle is not within specifications, repair or adjust to obtain the correct angles.
Inspect the powertrain/drivetrain mounts or frame rails for wear or damage. Klj . 2 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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DESCRIPTION AND OPERATION
Rear Drive Halfshafts
The rear wheel drive halfshaft system consists of and operates as follows:
zHalfshafts (4K138) transmit engine torque from the rear axle housing to the rear wheels.
z Halfshafts rotate at approximately one- third the speed of a driveshaft and do not contribute to
rotational vibration disturbances.
z A constant velocity (CV) joint is a mechanism for transmitting uniform torque and rotary motion
while operating through a range of angles.
z CV joints at both inboard (differential) and outboard (wheel) ends provide operating
smoothness.
z The inboard CV joints are plunge- type joints that provide the axial movement necessary to
affect shaft length changes.
z The outboard CV joints have a higher angle capability than the inboard CV joints to
accommodate suspension travel.
z Inboard and outboard CV joints connect to a splined shaft.
z A driveshaft bearing retainer circlip retains the splined inboard CV joint to the differential side
gear. Install a new circlip every time you remove the halfshaft from the vehicle.
z A rear axle wheel hub retainer secures the interconnecting shaft and outboard CV joint to the
rear hub.
z The lubed-for- life CV joints use special CV joint grease. They require no periodic lubrication.
z To separate the halfshaft from the rear hub, press the outboard CV joint from the rear hub.
z To separate the halfshaft from the differential, apply a load to the back face of the inboard CV
joint assembly to overcome the circlip.
z The halfshaft assemblies are not repairable. Install a new assembly if worn/damaged.
SECTION 205-
05: Rear Drive Halfshafts 2003 Mustang Workshop Manual Klj . 1 ba
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