Ford Mustang (1999-2004) Service Manual: Gear Howl and Whine

Howling or whining of the ring gear and pinion is due to an incorrect gear pattern, gear damage or incorrect bearing preload.

Wheel Hub or Axle Flange Face Runout
NOTE: If the axle shaft assembly is removed, check runout of the shaft itself. The forged (unmachined) part of the shaft is allowed to have as much as 3.0 mm (0.120 inch) runout. This alone will not ...

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. ...

Other materials:

Valve Stem to Valve Guide Clearance
Special Tool(s) Dial Indicator Gauge with Holding Fixture 100-002 (TOOL-4201-C) or equivalent Clearance Gauge, Valve Guide 303-004 (TOOL-6505-E) or equivalent NOTE: Valve stem diameter must be within specifications before checkin ...

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 ...

Spring
Special Tool(s) Tie-Rod End Remover 211-001 (TOOL-3290-D) or Equivalent Coil Spring Compressor 204-D001 (D78P-5310-A) or Equivalent ...