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:
Module - Daytime Running Lamps (DRL)
Removal
1. CAUTION: Electronic modules are sensitive to static electrical
charges. If exposed
to these charges, damage can result.
Disconnect the battery ground cable.
2. Remove the daytime running lamps (DRL) module and bracket assembly
(15A270).
...
Removal
1. Disconnect the battery ground cable. For additional information, refer to
Section.
2. Remove the transmission.
3. Remove the air intake scoop. For additional information, refer to Section.
4. Remove the air cleaner outlet tube. For additional informatio ...
Refrigerant Oil Adding
CAUTION: During normal A/C operation, oil is circulated through the
system with the
refrigerant, and a small amount is retained in each component. If certain
components of the
system are removed for new installation, some of the refrigerant oil will go
with ...
