Symptom Chart - NVH: Notes

2007 Ford Fusion SEL, 2.3 Z, StandardSECTION Notes
WARNING: This page is about a different car, the 2010 Lincoln Town Car. However, it is still accessible from the selected car via links, so may be relevant.
NOTE: NVH symptoms should be identified using the diagnostic tools that are available. For a list of these tools, an explanation of their uses and a glossary of common terms, refer to NOISE, VIBRATION & HARSHNESS article. Since it is possible any one of multiple systems may be the cause of a symptom, it may be necessary to use a process of elimination type of diagnostic approach to pinpoint the responsible system. If this is not the causal system for the symptom, refer back to NOISE, VIBRATION & HARSHNESS article for the next likely system and continue diagnosis.
Symptom Chart - NVH

Condition Possible Sources Action
  • Axle howling or whine
  • Axle lubricant low
  • CHECK the lubricant level. FILL the axle to specification.
 
  • Axle housing damage
 
  • Damaged or worn axle shaft bearings
 
  • Damaged or worn differential ring and pinion
 
  • Damaged or worn differential side or pinion bearings
  • Driveline clunk - loud clunk when shifting from REVERSE to DRIVE
  • Incorrect axle lubricant level
  • CHECK the lubricant level. FILL the axle to specification.
 
  • Excessive backlash in the axle
 
  • Damaged or worn pinion bearings
 
  • Damaged or worn U-joints
  • INSPECT the U-joints for wear or damage. INSTALL new U-joints or driveshaft as necessary. REFER to DRIVESHAFT article.
  • Driveline clunk - occurs as the vehicle starts to move forward following a stop
  • Worn driveshaft U-joints with excessive play
  • INSPECT the U-joints for a worn condition. INSTALL a new driveshaft or U-joints as necessary. REFER to DRIVESHAFT article.
 
  • Loose rear axle mount
  • High pitched chattering - noise from the axle when the vehicle is turning
  • Incorrect or contaminated lubricant
  • CHECK the vehicle by driving in tight circles (5 clockwise, 5 counterclockwise). FLUSH and REFILL with the specified rear axle lubricant and friction modifier as necessary.
 
  • Damaged or worn differential (differential side gears and pinion gears)
  • Buzz - buzzing noise is the same at cruise or coast/deceleration
  • Incorrect driveline angles
  • Rumble or boom - noise occurs at coast/deceleration, usually driveshaft speed-related and noticeable over a wide range of speeds
  • Driveshaft is out-of-balance
 
  • U-joints are binding or seized
  • ROTATE the driveshaft and CHECK for rough operation or seized U-joints. INSTALL new U-joints or driveshaft as necessary. REFER to DRIVESHAFT article.
  • Grunting - normally associated with a shudder experienced during acceleration from a complete stop
  • Loose rear axle mount bolts or suspension fasteners
  • Howl - can occur at various speeds and driving conditions. Affected by acceleration and deceleration
  • Incorrect ring and pinion contact, incorrect bearing preload or gear damage
  • Chuckle - heard at coast/deceleration. Also described as a knock
  • Incorrect ring and pinion contact or damaged teeth on the coast side of the ring and pinion
  • Knock - noise occurs at various speeds. Not affected by acceleration or deceleration
  • Gear tooth damage to the drive side of the ring and pinion
  • Scraping noise - a continuous low pitched noise starting at low speeds
  • Worn or damaged pinion bearings
  • Driveline shudder - occurs during acceleration from a slow speed or stop
  • Rear drive axle assembly mispositioned
 
  • Loose rear axle bolts
 
  • Driveline angles out of specification
 
  • U-joints binding or seized
  • ROTATE the driveshaft and CHECK for rough operation or seized U-joints. INSTALL new U-joints or driveshaft as necessary. REFER to DRIVESHAFT article.
  • Driveline vibration - occurs at cruising speeds
  • Worn U-joints
  • CHECK for wear or incorrect seating. INSTALL new U-joints or driveshaft as necessary. REFER to DRIVESHAFT article.
 
  • Loose axle pinion flange bolts
  • INSPECT the axle pinion flange. TIGHTEN the pinion flange bolts to specification. REFER to DRIVESHAFT article.
 
  • Excessive axle pinion flange runout
 
  • Driveshaft is out-of-balance
  • CHECK the driveshaft for damage, missing balance weights or undercoating. CHECK the driveshaft balance. CARRY OUT a driveline vibration test. REFER to Driveshaft Runout and Balancing .
 
  • Excessive driveshaft runout
 
  • Driveline angles out of specification
RENDER: 1.0x

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • You smell fuel, burning insulation, or see smoke.
  • Brakes feel soft, pull hard to one side, or make grinding noises.
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