Symptom Charts - NVH: Notes

2007 Ford Escape Base, 2.3 Z, FWD, AutomaticSECTION Notes
WARNING: This page is about a different car, the 2010 Mercury Mariner and 2010 Ford Escape. 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 . 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 DIAGNOSIS AND TESTING for the next likely system and continue diagnosis.
SYMPTOM CHARTS - 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
  • INSPECT the axle housing for damage. REPAIR or INSTALL a new axle as necessary. REFER to IN-VEHICLE REPAIR .
  • Damaged or worn wheel hub 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 REMOVAL AND INSTALLATION .
  • 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 REMOVAL AND INSTALLATION .
  • Loose rear axle mount
  • Driveline clunk (Front Wheel Drive (FWD) vehicles) - occurs during acceleration or from cruise to coast/deceleration
  • Damaged or worn inner CV joint
  • Clicking, popping or grinding - occurs while the vehicle is turning
  • Inadequate or contaminated lubrication in the CV joints
  • CHECK the CV boots and joints for wear or damage. INSTALL new components as necessary. REFER to REMOVAL AND INSTALLATION .
  • Another component contacting the halfshaft
  • CHECK the halfshafts and the area around the halfshafts. REPAIR as necessary.
  • 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 REFILL with the specified rear axle lubricant and friction modifier as necessary. REFER to DIFFERENTIAL HOUSING COVER .
  • 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 DISASSEMBLY AND ASSEMBLY .
  • Grunting - normally associated with a shudder experienced during acceleration from a complete stop
  • Driveshaft CV joint binding
  • Loose rear axle mount bolts or suspension fasteners
  • INSPECT the rear suspension and axle. TIGHTEN the fasteners to specification. REFER to TORQUE SPECIFICATIONS .
  • 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
  • CHECK the rear axle for loose bolts. TIGHTEN the bolts to specification. REFER to TORQUE SPECIFICATIONS .
  • 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 DISASSEMBLY AND ASSEMBLY .
  • 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 REMOVAL AND INSTALLATION .
  • 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 REMOVAL AND INSTALLATION .
  • 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 driveshaft as necessary. REFER to REMOVAL AND INSTALLATION .
  • Loose axle pinion flange bolts
  • INSPECT the axle pinion flange. TIGHTEN the pinion flange bolts to specification. REFER to TORQUE SPECIFICATIONS .
  • 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 REMOVAL AND INSTALLATION .
  • Excessive driveshaft runout
  • Driveline angles out of specification
  • Incorrectly seated CV joint in the wheel hub
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.
  • The engine overheats, stalls repeatedly, or misfires under load.
  • You are missing required tools, torque specs, or safe lifting equipment.
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