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:

Rear Suspension (Description and Operation)
  Item Part Number Description 1 18125 Rear shock absorber 2 - Rear axle driveline vibration damper 3 5A649 Rear lower suspension arm and bushing (common LH and RH) 4 5560 Rear spring 5 4731 ...

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 ...

Refrigerant System Tests
Special Tool(s) R-134a Manifold Gauge Set 176-R032A or equivalent 1. Connect the R-134a Manifold Gauge Set. For additional information, refer to Manifold Gauge Set Connection in this section. 2. Adjust the climate controls for maximum cooling ...