Ford Mustang (1999-2004) Service Manual: 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.

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.
Bearing Whine
Bearing whine is a high-pitched sound similar to a whistle. It is usually
caused by worn/damaged
pinion bearings, which are operating at driveshaft speed. Bearing noise occurs
at all driving speeds. ...
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 s ...
Other materials:
Rear Drive Halfshafts (Description and Operation)
The rear wheel drive halfshaft system consists of and operates as
follows:
Halfshafts (4K138) transmit engine torque from the rear axle housing to
the rear wheels.
Halfshafts rotate at approximately one-third the speed of a driveshaft
and do not cont ...
Anti-Lock Control
Refer to Wiring Diagrams Cell 42 , Anti-Lock Brake for schematic and
connector information.
Special Tool(s)
Worldwide Diagnostic System
(WDS)
418-F224,
New Generation STAR (NGS)
Tester
418-F052, or equivalent scan
tool
73 Digita ...
Inspection and Verification
1. Verify the customer's concern by operating the active restraint system to
duplicate the condition.
2. Inspect to determine if any of the following mechanical or electrical
concerns apply:
Visual Inspection Chart
Mechanical
Electrical
...
