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Symptom Chart - NVH: Notes

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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 . 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 for the next likely system and continue diagnosis.
SYMPTOM CHART - NVH

Condition Possible Sources Action
  • Axle howling or whine - front or rear axle
  • Axle lubricant low
  • CHECK the lubricant level. FILL the axle to specification.
  • Axle housing damage
  • Damaged or worn wheel bearings or axle 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 as necessary. REFER to DRIVESHAFT .
  • Driveline clunk - occurs as the vehicle starts to move forward following a stop
  • Worn driveshaft CV joint or U-joints with excessive play
  • INSPECT the CV joint and U-joints for a worn condition. INSTALL a new driveshaft or U-joints as necessary. REFER to DRIVESHAFT .
  • Loose rear axle mount
  • High pitched chattering - noise from the rear axle when the vehicle is turning
  • Incorrect or contaminated lubricant
  • CHECK the vehicle by driving in tight circles (5 clockwise, 5 counterclockwise). FLUSH and FILL 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
  • Driveline angles out of specification
  • 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 as necessary. REFER to DRIVESHAFT .
  • Grunting - normally associated with a shudder experienced during acceleration from a complete stop
  • Driveshaft CV joint binding
  • INSTALL a new driveshaft as necessary. REFER to DRIVESHAFT .
  • Loose rear axle mount bolts or suspension fasteners
  • INSPECT the rear suspension and axle. TIGHTEN the fasteners to specification.
  • 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 (vehicle unloaded)
  • Rear drive axle assembly mispositioned
  • CHECK the axle mounts and the rear suspension for damage or wear. REPAIR as necessary.
  • Loose axle mounting 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 as necessary. REFER to DRIVESHAFT .
  • Binding or damaged driveshaft CV joint
  • INSPECT the driveshaft CV joint and coupling shaft for wear or damage. INSTALL a new driveshaft as necessary. REPAIR as necessary. REFER to DRIVESHAFT .
  • Driveline shudder - occurs during acceleration from a slow speed or stop (vehicle loaded)
  • Driveline angles out of specification due to loaded condition
  • Driveline vibration - occurs at cruising speeds
  • Worn U-joints
  • CHECK for wear or incorrect seating. INSTALL new U-joints as necessary. REFER to DRIVESHAFT .
  • Worn or damaged driveshaft center bearing support
  • CHECK the insulator for damage or wear. ROTATE the driveshaft and CHECK for rough operation. INSTALL a new center bearing support as necessary. REFER to DRIVESHAFT .
  • Loose axle pinion flange bolts
  • INSPECT the axle pinion flange. TIGHTEN the pinion flange bolts to specification. REFER to DRIVESHAFT .
  • 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 .
  • Binding or damaged driveshaft CV joint
  • INSPECT the driveshaft CV joint for wear or damage. INSTALL a new driveshaft as necessary. REFER to DRIVESHAFT .
  • Excessive driveshaft runout
  • Driveline angles out of specification
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