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:
Ignition Switch Lock Cylinder - Functional
Removal and Installation
1. Disconnect the battery ground cable.
2. Remove the ignition switch lock cylinder (11582).
1. Insert the ignition key and turn to the RUN position.
2. Using a 1/8-inch drift, press the ignition switch lock cylinder release
...
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 th ...
Inspection and Verification
1. The interior lighting system is a generic electronic module (GEM)
controlled system.
2. Verify the customer concern by operating the interior lighting system.
3. Visually inspect for the following obvious signs of mechanical and
electrical damage.
...
