2003 FORD MUSTANG 4WD

Neutral Coast Down Speed Test
To carry out this test, proceed as follows:
zDrive at a higher rate of speed than where the concern occurred when carrying out the Slow
Acceleration Test.
z Place the transmission in NEUTRAL and coast down past the speed where the concern occurs.
z The concern is vehicle speed- related if duplicated while carrying out this test. This eliminates
the engine and the torque converter as sources.
z If the concern was not duplicated while carrying out this test, carry out the Downshift Speed
Test to verify if the concern is engine speed related.
z Proceed as necessary.
Downshift Speed Test
To carry out this test, proceed as follows:
zShift into a lower gear than the gear used when carrying out the Slow Acceleration Test.
z Drive at the engine rpm where the concern occurs.
z The concern is engine speed related if duplicated while carrying out this test. This eliminates the
tires, wheels, brakes and the suspension components as sources.
z If necessary, repeat this test using other gears and NEUTRAL to verify the results.
z Proceed as necessary.
Steering Input Test
To carry out this test, proceed as follows:
zDrive at the speed where the concern occurs, while making sweeping turns in both directions.
z If the concern goes away or gets worse, the wheel bearings, hubs, U- joints (contained in the
axles of 4WD applications), and tire tread wear are all possible sources.
z Proceed as necessary.
Brake Test
To carry out this test, proceed as follows:
zWarm the brakes by slowing the vehicle a few times from 80–32 km/h (50–20 mph) using light
braking applications. At highway speeds of 89–97 km/h (50– 60 mph), apply the brake using a
light pedal force.
z Accelerate to 89–97 km/h (55–60 mph).
z Lightly apply the brakes and slow the vehicle to 30 km/h (20 mph).
z A brake vibration noise can be felt in the steering wheel, seat or brake pedal. A brake noise can
be heard upon brake application and diminish when the brake is released.
Road Test Over Bumps
To carry out this test, proceed as follows: Klj . 7 ba
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components as necessary.
z Broken
powertrain
mounts. z
INSPECT the powertrain
mounts. INSTALL new
mounts as necessary.
REFER to Section 303 - 01A
for 3.8L engines or
Section 303 - 01B for 4.6L (2V)
engines.
z Idle speed too
high. z
CHECK for the correct idle
speed.
z Driveline clunk—
occurs as the vehicle
starts to move
forward following a
stop z
Worn or galled
driveshaft slip-
yoke splines. z
CLEAN and INSPECT the
splines of the yoke for a
worn or galled condition.
INSTALL a new yoke as
necessary. REFER to
Section 205 - 01 .
z Worn or galled
driveshaft and
coupling shaft
splines. z
CLEAN and INSPECT the
splines of the driveshaft and
coupling shaft for a worn or
galled condition. INSTALL a
new driveshaft assembly as
necessary. REFER to
Section 205 - 01 .
z Loose rear leaf
spring U- bolts. z
CHECK the U- bolts for
loose nuts. TIGHTEN to
specification. REFER to
Section 204 - 02 .
z Driveline clunk (FWD
vehicles)—occurs
during acceleration or
from cruise to
coast/deceleration z
Damaged or
worn inboard
constant velocity
(CV) joint. z
INSPECT the inboard CV
joint and boot. REPAIR or
INSTALL a new CV joint as
necessary.
z Driveline clunk (4WD
vehicles)—occurs
during shift- on-the- fly
engagement z
Clutch relay.
z Shift motor.
z Transfer case.
z GEM. z
CHECK the 4WD
engagement system.
REPAIR or INSTALL new
components as necessary.
z Clicking, popping or
grinding— occurs
while vehicle is
turning z
Inadequate or
contaminated
lubrication in the
(CV) joints. z
CHECK the CV boots and
joints for wear or damage.
REPAIR or INSTALL new
components as necessary.
z Another
component
contacting the
halfshaft. z
CHECK the halfshafts and
the area around the
halfshafts. REPAIR as
necessary.
z Brake
components. z
INSPECT the front brakes
for wear or damage.
REPAIR as necessary.
REFER to Section 206 - 03 .
z Steering
components. z
INSPECT the drag link,
inner and outer tie- rods or
idler arm for wear or
damage. REPAIR as
necessary. REFER to
Section 211 - 02 .
z Suspension
components. z
INSPECT the upper and
lower ball joints for wear or
damage. REPAIR as
necessary. REFER to Klj . 19 ba
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information, REFER to
Section 205
- 00 .
REPAIR as necessary.
z Transmission
rumble/growl— noise at
all speeds in forward
gears, more
pronounced in a heavy
acceleration condition z
Damaged or worn
transmission
bearing or gears
(high mileage
vehicles). z
CHECK transmission
fluid for excessive
metal particles.
REPAIR as necessary.
REFER to Section 308 -
03A for T50D
transmissions or
Section 308 - 03B for
TR3650 transmissions.
z Transfer case whine—
noise at all ranges z
Incorrect fluid level
or fluid quality. z
CHECK that the
transfer case is filled to
the correct level and
with the specified fluid.
REFER to Section 308 -
03A for T50D
transmissions or
Section 308 - 03B for
TR3650 transmissions.
z Worn oil pump. zDISASSEMBLE the
transfer case. CHECK
the oil pump for wear or
damage. REPAIR as
necessary.
z Under- inflated or
oversized tires. z
CONFIRM that the tires
and wheels are correct
for the vehicle. CHECK
that the tire inflation
pressures are correct.
z Transfer case
growl/rumble— noise at
all ranges (A small
amount of planetary
noise can be heard
when the transfer case
is operated in low
range.) z
Damaged or worn
bearings or
planetary gear. z
DISASSEMBLE the
transfer case. CHECK
the bearings or
planetary gear for wear
or damage. REPAIR as
necessary.
z Transfer case
scraping/grating—
noise at all ranges z
Excessively
stretched drive
chain hitting the
case. z
DISASSEMBLE the
transfer case. CHECK
the drive chain for wear
or damage. REPAIR as
necessary.
z Transfer case
howl/hum— noise at all
ranges or high range
only z
Worn or damaged
sun (input) gear,
clutch pack
(intermediate) gear
or output shaft gear. z
DISASSEMBLE the
transfer case. CHECK
the gears for wear or
damage. REPAIR as
necessary.
z Transfer case
howl/hum— noise at
low range only z
Worn or damaged
intermediate gear
and sliding gears
(clutch pack). z
DISASSEMBLE the
transfer case. CHECK
the gears for wear or
damage. REPAIR as
necessary.
z Transfer case
vibration— vibration felt
with vehicle in 4WD z
Transfer case
mounting.
z Driveshaft out of
balance.
z Excessive pinion z
Go To Pinpoint Test M . Klj . 44 ba
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Component Tests
Idle Air Control (IAC) Valve
1. Open the hood.
2. NOTE: Key symptom is elevated idle speed while noise is occurring.
NOTE: "Snapping" the throttle can induce the noise.
Verify the condition by operating the vehicle for a short time.
3. Inspect the IAC valve. If physical evidence of contamination exists, install a new IAC valve. GO to
M4 .
M4 INSPECT THE FRONT DRIVESHAFT
z
NOTE: Verify that the driveshaft and pinion flange index marks
are aligned.
z Inspect the front driveshaft for missing weights, damage or
undercoating.
z Inspect the U- joints and slip yoke for freedom of movement.
z Check driveshaft runout and, if necessary, check the pinion
flange runout.
z Is the driveshaft or U- joints worn or damaged? Yes
REPAIR or INSTALL a
new driveshaft as
necessary. TEST the
system for normal
operation.
No
GO to
M5 .
M5 ROAD TEST WITH THE FRONT DRIVESHAFT ONLY
z
NOTE: Index mark the driveshaft to the pinion flange and to the
output shaft before removal.
z Remove the rear driveshaft.
z Plug the transfer case with an output shaft seal plug.
z NOTE: Shift the transfer case into 4WD high so the vehicle is
driven by the front driveshaft only.
z Test drive the vehicle.
z Is the vibration gone? Yes
INSTALL and BALANCE
the rear driveshaft.
TEST the system for
normal operation.
No
GO to
M6 .
M6 ROAD TEST WITH THE REAR DRIVESHAFT ONLY
z
NOTE: Index mark the front driveshaft to the pinion flange.
z Remove the front driveshaft.
z Test drive the vehicle.
z Is the vibration gone? Yes
INSTALL and BALANCE
the front driveshaft.
TEST the system for
normal operation.
No
GO to
M7 .
M7 TRANSFER CASE TAIL SHAFT INSPECTION
z
Inspect the splines of the output shaft for wear or damage.
z Inspect the splines of the driveshaft slip yoke for wear or
damage.
z Are the splines worn or damaged? Yes
REPAIR or INSTALL
new components as
necessary. TEST the
system for normal
operation.
No
The transfer case is OK.
CONDUCT a diagnosis
on other suspect
systems. Klj . 63 ba
702003 Mustang Workshop Manual
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