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:
Cleaning the interior
WARNING: Do not use cleaning solvents, bleach or dye on the
vehicle’s safety belts, as these actions may weaken the belt
webbing.
WARNING: On vehicles equipped with seat-mounted airbags, do
not use chemical solvents or strong detergents. Such products
could ...
Camshaft Journal - Clearance, Plastigage Method
Special Tool(s)
Plastigage
303-D031 (D81L-6002-B) or
equivalent
NOTE: The camshaft journals must meet specifications before checking
camshaft journal clearance.
1. Remove the camshaft bearing cap and lay Plastigage across the surface. Refer ...
Symptom Chart
NOTE: New speed control diagnostic software is available in Version 12
or higher for the diagnostic
tool. When using this software, it is necessary to use Next Generation Speed
Control Adapter 007-
00586 with the diagnostic tool.
NOTE: Refer to the Wiring Di ...
