Section 00-04: Noise, Vibration and Harshness
1996 F-150, F-250, F-350, Bronco and F-Super Duty Workshop Manual
DIAGNOSIS AND TESTING

Symptom Charts

ROAD TEST DIAGNOSIS
ConditionPossible SourceAction
  • Noise Is the Same on Drive or Coast
  • Road noise.
  • Vehicle OK.
 
  • Tire noise.
 
  • Front wheel bearing noise.
  • INSPECT/REPLACE front wheel bearings. REFER to appropriate section in Group 04 (2-wheel drive) or Group 05 (4-wheel drive).
 
  • Differential bearings.
  • INSPECT differential bearings. REFER to appropriate section in Group 05.
 
  • Pinion bearings.
  • INSPECT pinion bearings. REFER to appropriate section in Group 05.
  • Noise Changes with Type of Road Surface
  • Road noise.
  • Vehicle OK.
 
  • Tire noise.
  • Noise Tone Lowers As Vehicle Speed Lowers
  • Tire noise.
 
  • Driveline noise.
  • INSPECT driveshaft, U-joints and rear axle universal joint flange. REFER to Section 05-00. For removal of driveshaft, REFER to Section 05-01.
  • Similar Noise Is Produced with Vehicle Standing or Driving
  • Accessory noise.
 
  • Transmission noise.
  • INSPECT transmission and mount. REFER to appropriate section in Group 07.
 
  • Engine noise.
  • Noise Most Pronounced on Turns
  • Front or rear wheel bearings.
  • INSPECT front/rear wheel bearings. REFER to appropriate section in Group 04 (2-wheel drive) or Group 05 (4-wheel drive) for front and rear wheel bearings.
 
  • Differential side gears and pinion gears.
  • INSPECT/REPLACE faulty gears or clutch packs (if equipped with limited slip). REFER to appropriate section in Group 05.
  • Drive Noise, Coast Noise
  • Wheel bearings.
  • INSPECT front/rear wheel bearings. REFER to appropriate section in Group 04 for front wheel bearings on 4x2 vehicles or Group 05 for front and rear wheel bearings on 4x4 vehicles.
 
  • Ring and pinion gear.
  • PERFORM Pinpoint Test G. INSPECT ring and pinion gear. REFER to appropriate section in Group 05.
  • Clunk on Acceleration or Deceleration
  • Inoperative throttle damper.
  • REFER to appropriate section in Group 03.
 
  • Loose suspension components.
  • INSPECT suspension. REFER to appropriate section in Group 04.
 
  • Worn and/or loose driveshaft U-joints/rear axle universal joint flange.
 
  • Worn driveshaft slip-yoke splines or sticking slip-yoke.
 
  • Loose engine mounts.
 
  • Excessive ring and pinion gear backlash.
 
  • Transmission (backlash).
  • REFER to appropriate section in Group 07.
  • Noise Is Different When Transmission in Drive During Coasting and When in Neutral During Coasting
  • Axle.
 
  • Transmission.
  • INSPECT transmission. REFER to appropriate section in Group 07.
  • Gear Howl and Whine
  • Ring gear runout.
  • Insufficient bearing preload.
  • Ring and pinion gear backlash.
  • Worn ring and pinion gears.
  • Chuckle Noise
  • Broken gear teeth.
  • Ring and pinion gear clearance.
  • Knock Noise
  • Axle shaft end play.
  • INSPECT and repair axle shafts. REFER to appropriate section in Group 05.
AXLE DIAGNOSIS REAR
ConditionPossible SourceAction
  • Vibration and Boom
  • Ring gear and pinion.
  • Rear Axle Noise
  • Differential carrier.
  • Axle shafts.
  • Lubricant.
  • Loud "Clunk" in the Driveshaft When Shifting from Reverse to Forward
  • Driveshaft.
 
  • Rear axle shaft or carrier.
  • On Turns, the Rear Axle Has a Chattering Noise (Limited Slip or Traction-Lok® Axles Only). Slight Chatter or Groaning Noise on Slow Turns After Extended Highway Driving Is Considered Acceptable and Has No Detrimental Effect on the Limited Slip Axle Functions.
  • Lubricant.
  • Differential.
ACCESSORY DRIVE DIAGNOSIS
ConditionPossible SourceAction
  • Excessive Noise
  • Seized accessory.
  • Belt Squeal
  • Loose belt.
  • Noisy Accessory
  • Worn accessory bearings.
  • Loose bolts/brackets.
  • Rattle
  • Loose pulley, accessory or bracket.
  • Noisy Tensioner Pulley Bearing
  • Worn bearing.
  • Belt Chirp
  • Misaligned power steering pulley.
  • Severe Belt Flutter
  • Loose belt.
  • Binding tensioner arm.
 
NOISE, VIBRATION AND HARSHNESS DIAGNOSIS
ConditionPossible SourceAction
  • Shake/Vibration in Drive Under Acceleration/Deceleration
  • Tires/wheels.
  • Loose or misadjusted wheel bearings.
  • Brake rotors/drums brake imbalance.
  • Suspension/steering linkage.
  • Engine/transmission.
  • Tip-In Moan
  • Air cleaner.
  • Engine mounts.
  • Exhaust.
  • Idle Boom/Shake/Vibration
  • Engine control cables or hoses.
  • Engine mounts.
  • Exhaust.
  • Drive belts and pulleys.
  • Engine Accessory Vibration
  • Drive belts and pulleys.
  • Mounting hardware.
  • Accessories.
  • Driveshaft Vibration
  • Driveshaft runout indexing (axle/transmission), rear axle universal joint flange, and balance.
  • Tire/Wheel Runout
  • Imbalanced tires.
  • Damaged tire/wheel.
  • Brakes Vibration/Shudder
  • Brake shoes/pads.
  • Brake rotors/drums.
  • Brake calipers/wheel cylinders.
  • Axle Gear Noise
  • Improper or low axle fluid lubricant.
  • Axle shaft splines.
  • Differential gears.
  • Broken ring gear bolts.
  • Broken teeth on gears.
  • Incorrect clearance between axle gears (ring and pinion).
  • Worn pinion gear/bearings.
  • Noise or Vibration 4-WD Vehicles
  • Wheels/tires.
 
  • Wheel bearings.
 
  • Driveshafts/U-joints.
 
  • Hubs, automatic or manual locking.
 
  • Engine/transmission mounts.
 
  • Transfer case.
 
  • Engine/transmission.
  • Driveshaft Joint Noise and Vibration
  • Worn U-joints.
  • Center bearing support (driveshaft).
  • Worn slip-yoke.
  • Worn or damaged driveshaft.
  • Non-Axle Noise
  • Grille whistle.
  • Trim moulding.
  • Roof top luggage rack (if equipped).
  • Drive belt squeal or chirp.
  • Tires.
  • A/C system.
  • Exhaust.
  • Aftermarket add-ons (running boards, grounding body to frame, antennas, visors, bug deflectors, etc.).
  • Axle Noise
  • Bent or damaged axle housing.
  • Axle shafts.
  • Bearings.
  • Wheel End Vibration Analysis
  • Tires/wheels.
  • Worn or damaged wheel bearing.
  • Brake drum/rotor imbalance.
  • Engine or transmission mounts.
  • Engine Run-Up Check
  • A/C system.
  • Exhaust.
  • Transmission.
  • Engine.
  • Drive Belt Check
  • Drive Belt and/or pulleys.