Ford Mustang (1999-2004) Service Manual: Symptom Charts

Symptom Chart - Air Leak and Wind Noise

Condition Possible Sources Action
  • Air leak around door perimeter
  • Loose fit seal.

  • Seal installed incorrectly.

  • Door misaligned.

  • Scuff plate installed incorrectly.

  • Seal or seal push pins damaged.
  • PINCH the seal carrier to improve retention on the seal flange.
  • REINSTALL the seal.
  • REALIGN the door.

    CHECK door gaps and fit in the door opening and ADJUST as necessary.

  • REINSTALL the scuff plate.
  • INSTALL a new seal.
  • Air leak around glass run
  • Door glass misaligned.
  • Glass run installed incorrectly.
  • Leak path behind glass run.
  • Glass run channel spread wide.
  • Blow-out clip bent or contacting door glass.
  • Glass run damaged.
  • ADJUST the door glass.
  • ADJUST the glass run.

    INSERT foam in the glass run carrier.

  • INSTALL foam rope behind the glass run.
  • PINCH the glass run channel to reduce the size of the opening.
  • ADJUST the blow-out clip or INSTALL a new glass run/blow-out clip molding assembly.
  • INSTALL a new glass run.
  • Air leak at inner belt line
  • Belt line seal installed incorrectly on flange.
  • Belt line seal integrated with door trim installed incorrectly (no glass contact).
  • No contact with side glass.
  • No contact with glass runs at both ends of belt line seal.
  • Belt line seal damaged.
  • ADJUST the seal. (Do not bend the flange.)
  • REINSTALL the door trim.
  • ADJUST the door glass.
  • ADJUST the belt line seal or ADD foam at the seal ends.
  • INSTALL a new seal.
  • Air leak at outer belt line
  • Belt line seal installed incorrectly on flange (no glass contact).
  • Belt line seal does not contact the glass.
  • No contact with glass runs at both ends of belt line seal.
  • Belt line seal damaged.
  • ADJUST the seal.
  • ADJUST the door glass.
  • ADJUST the belt line seal/ADD foam at the seal ends.
  • INSTALL a new seal.
  • Draft at inner door handle/speaker opening
  • Hole in watershield.
  • Watershield misaligned.
  • Exterior door handle seal misaligned/damaged.
  • SEAL the hole with a suitable tape.
  • REALIGN the watershield.

    INSTALL a new watershield if the pressure sensitive adhesive fails.

  • REALIGN or INSTALL a new seal as necessary.
  • Wind noise from side view mirror
  • Outside mirror housing misaligned.
  • Mirror sail gasket folded/misaligned.
  • Mirror housing trim cap installed incorrectly.
  • Air leak through mirror housing hinge.
  • Inner sail trim installed incorrectly.
  • Inner sail gasket/barrier installed incorrectly.
  • Air path through wiring bundle/fastener access holes.
  • Exposed fastener access hole on mirror housing/sail.
  • REALIGN with the edges shingled correctly and no gaps.
  • REINSTALL with the gasket unfolded and aligned correctly.
  • REINSTALL with the edges shingled to the air flow.
  • Fully ENGAGE the mirror into its operating position/USE foam to block the air path through the hinge.
  • REINSTALL the sail trim/ADJUST the door trim.
  • REINSTALL the trim cover with the gasket/barrier aligned correctly.
  • BLOCK the air path(s) with foam/tape.
  • INSTALL a new cap if it is missing.
  • Air leak around perimeter of fixed glass
  • Gaps in the sealant bead.
  • Air traveling up windshield molding along A-pillar.
  • Windshield/backlite misaligned or not installed correctly.
  • Rear hood seal at base of windshield misaligned/damaged.
  • APPLY approved sealant
  • INSTALL foam rope the full length of the A-pillar.
  • REINSTALL the windshield/backlite.
  • REALIGN or INSTALL a new seal as necessary.
  • Air leak at cowl
  • Cowl gasket misaligned/damaged.
  • REALIGN or INSTALL a new seal as necessary.
  • Air leak around liftgate perimeter
  • Loose fit seal.
  • Seal misaligned.
  • Liftgate misaligned.
  • Scuff plate misaligned.
  • Seal or seal push pins damaged.
  • PINCH the seal carrier to improve retention on the seal flange or INSERT foam in the carrier.
  • REINSTALL the seal.
  • REALIGN the liftgate.

    CHECK the liftgate fit in the body opening and ADJUST as necessary.

  • REINSTALL the scuff plate.
  • INSTALL a new seal.
  • Air leak around the liftgate flip window perimeter
  • Loose fit seal.
  • Seal misaligned.
  • Glass misaligned.
  • Seal damaged.
  • PINCH the seal carrier to improve the retention to the seal flange.
  • REINSTALL the seal.
  • REALIGN the glass.
  • INSTALL a new seal.
  • Wind noise from antenna
  • Shape of antenna.
  • Air leak around antenna cable access hole.
  • INSTALL an antenna boot or a spiral antenna.
  • INSPECT the antenna access hole grommet.

    REPAIR as necessary.
  • Air leak from closed roof opening panel
  • Seal installed incorrectly.
  • Roof opening panel glass/door misaligned.
  • Roof opening panel damaged.
  • REINSTALL the seal.
  • REALIGN the roof opening panel glass/door.
  • INSTALL a new roof opening panel.
  • Buffeting from an open roof opening panel
  • Wind deflector inoperative/damaged
  • Wind deflector height incorrect.
  • REPAIR or INSTALL a new wind deflector as necessary
  • ADJUST the wind deflector higher.
  • Wind noise created by airflow over or behind body panels
  • Fender splash shield misaligned
  • Body panel misaligned (exposed edge).
  • Hood misaligned (front margin).
  • Front grille edge noise.
  • REALIGN the fender splash shield.
  • REALIGN the appropriate body panel.
  • CHECK hood gaps and fit.

    ADJUST the hood as necessary

  • APPLY foam in the hollow areas behind the louvers
  • Wind noise created by grille opening panel
  • Grille relationship to leading edge on hood.
  • Sharp edges due to material imperfections
  • ADJUST the grille opening panel forward to eliminate wind noise
  • REMOVE the sharp edges (no damage to visible surface).
  • Wind noise from air extractor
  • Air extractor housing seated incorrectly.
  • Air extractor housing or flaps damaged.
  • REINSTALL the air extractor housing.
  • INSTALL a new air extractor
  • Air leak at top of A-pillar - vehicles with a convertible top
  • Seal at windshield header installed incorrectly
  • Seal pinched.
  • Gap between side rail and header seal at Apillar.
  • REINSTALL the seal.
  • FILL the seal with foam to reshape it.
  • ADJUST the J-hook/vinyl top
  • Air leak at rear quarter glass (division bar) - vehicles with a convertible top
  • No contact between front side glass and quarter glass division bar.
  • ADJUST the front side glass regulator and the rear quarter glass regulator
  • Air leak or wind noise from top of side glass - vehicles with a convertible top
  • Gap between side rail and vinyl top.
  • Seal at windshield header installed incorrectly
  • Seal damaged between side rail and vinyl top
  • Vinyl top damaged.
  • ADD additional foam tape to seal between the side rail and the vinyl top.
  • REINSTALL the seal.
  • INSTALL a new seal.
  • INSPECT the vinyl top.

    INSTALL a new vinyl top as necessary.
  • Air leak or wind noise at windshield header - vehicles with a convertible top
  • Vinyl top not flush with header.
  • Seal at windshield header installed incorrectly.
  • Header seal not flush with header.
  • ADJUST the J-hook to lower the top to achieve a flush condition
  • REINSTALL the seal.
  • REINSTALL the seal.
  • Convertible top flapping with the top up
  • Vinyl top contacting interior headliner.
  • Working from front to back, INSTALL a 6.35 mm (0.25 in) foam sheet between the headliner and the vinyl top at the suspected area. Allow a clearance of 50 mm (2 in) - 75 mm (3 in) away from the roof bows and the side rails
  • Noise from roof rack
  • Roof rack rails or crossbars loose.
  • Roof rack fasteners missing
  • Roof rack crossbars installed backward.
  • Roof rack rub strips partially lifting from roof
  • Roof rack gaskets loose or misaligned
  • TIGHTEN the fasteners.
  • INSTALL the approved fasteners.
  • REINSTALL the crossbars
  • REAPPLY adhesive or fasteners or INSTALL new rub strips as necessary.
  • REINSTALL the gasket.
  • Wind noise from bug shield/exterior windshield sun visor
  • Turbulence created by location and shape
  • REMOVE per customer direction if it is a dealer installed option

Symptom Chart-Brake Noise/Vibration

Condition Possible Sources Action
  • Rattling noise
  • Caliper mounting bolts loose.
  • Damaged or worn caliper pins or retainers.
  • Missing or damaged antirattle clips or springs.
  • Loose brake disc shield.
  • CHECK the caliper bolts.

    TIGHTEN to specifications.

  • CHECK the caliper pins and retainers for lubrication and correct fit. LUBRICATE or INSTALL new components as necessary.
  • CHECK the brake pads for missing clips or broken springs. INSTALL new components as necessary.
  • TIGHTEN the brake disc shield bolts to specification.
  • Clicking noise-with brakes applied with ABS brakes
  • ABS hydraulic control unit.
  • Acceptable condition.
  • Squealing noise-occurs on first (morning) brake application
  • Disc brake pads.
  • Acceptable condition. Caused by humidity and low disc brake pad temperature.
  • Squealing noise-a continuous squeal
  • Disc brake pads or linings worn below minimum thickness.
  • INSTALL new disc brake pads.
  • Squealing noise-an intermittent squeal brought on by cold, heat, water, mud or snow
  • Disc brake pad.
  • Acceptable condition.
  • Groaning noise- occurs at low speeds with brake lightly applied (creeping)
  • Disc brake pads.
  • Acceptable condition.
  • Grinding noise- continuous
  • Disc brake pads or linings worn below minimum thickness.
  • INSPECT the disc brake pads, brake discs and attaching hardware for damage. REPAIR or INSTALL new components as necessary
  • Moaning noise
  • Brake linings contaminated with grease or oil.
  • INSPECT the brake pads and shoes for contamination. REPAIR or INSTALL new components as necessary
  • Brake vibration/shudder- occurs when brakes are applied
  • Uneven disc or drum wear
  • Uneven disc brake pad or lining transfer.
  • Suspension components.
  • Go To Pinpoint Test A .
  • Brake vibration/shudder- occurs when the brake pedal is released
  • Brake drag.
  • INSPECT the disc brake pads or linings for premature wear. REPAIR or INSTALL a new caliper or wheel cylinder as necessary.

Symptom Chart-Driveline Noise/Vibration

Condition Possible Sources Action
  • Axle howling or whine-front or rear axle
  • Axle lubricant low.
  • 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.
  • Damaged or worn differential side gears and pinion gears.
  • CHECK the lubricant level.

    FILL the axle to specification.

  • INSPECT the axle housing for damage. REPAIR or INSTALL a new axle as necessary
  • CHECK for abnormal wheel bearing play or roughness.

    REFER to Wheel Bearing Check in this section.

    ADJUST or INSTALL new wheel bearings as necessary.

  • INSPECT the ring and pinion ring for abnormal wear patterns or broken teeth. INSTALL a new ring and pinion as necessary.
  • CHECK for abnormal bearing play or roughness.

    INSTALL new bearings as necessary.

  • DISASSEMBLE the differential carrier. INSPECT the side and pinion gears for abnormal wear patterns or broken teeth. INSTALL new gears as necessary
  • Driveline clunk-loud clunk when shifting from reverse to drive
  • Incorrect axle lubricant level.
  • Excessive backlash in the axle or transmission
  • Damaged or worn pinion bearings.
  • Damaged or worn universal joints (U-joints).
  • Loose suspension components.
  • Broken powertrain mounts.
  • Idle speed too high.
  • CHECK the lubricant level.

    FILL the axle to specification.

  • CARRY OUT a total backlash check.
  • CHECK for abnormal bearing play or roughness.

    INSTALL new bearings as necessary

  • INSPECT the U-joints for wear or damage. INSTALL new U-joints as necessary.
  • INSPECT the suspension for damage or wear.

    REPAIR or INSTALL new components as necessary.

  • INSPECT the powertrain mounts. INSTALL new mounts as necessary.
  • CHECK for the correct idle speed
  • Driveline clunk- occurs as the vehicle starts to move forward following a stop
  • Worn or galled driveshaft slipyoke splines
  • Worn or galled driveshaft and coupling shaft splines.
  • Loose rear leaf spring U-bolts.
  • CLEAN and INSPECT the splines of the yoke for a worn or galled condition.

    INSTALL a new yoke as necessary

  • CLEAN and INSPECT the splines of the driveshaft and coupling shaft for a worn or galled condition. INSTALL a new driveshaft assembly as necessary
  • CHECK the U-bolts for loose nuts. TIGHTEN to specification.
  • Driveline clunk (FWD vehicles)-occurs during acceleration or from cruise to coast/deceleration
  • Damaged or worn inboard constant velocity (CV) joint.
  • INSPECT the inboard CV joint and boot. REPAIR or INSTALL a new CV joint as necessary.
  • Driveline clunk (4WD vehicles)-occurs during shift-on-the-fly engagement
  • Clutch relay.
  • Shift motor.
  • Transfer case.
  • GEM.
  • CHECK the 4WD engagement system.

    REPAIR or INSTALL new components as necessary.
  • Clicking, popping or grinding-occurs while vehicle is turning
  • Inadequate or contaminated lubrication in the (CV) joints.
  • Another component contacting the halfshaft.
  • Brake components
  • Steering components.
  • Suspension components.
  • Damaged or worn wheel bearings
  • CHECK the CV boots and joints for wear or damage.

    REPAIR or INSTALL new components as necessary.

  • CHECK the halfshafts and the area around the halfshafts. REPAIR as necessary
  • INSPECT the front brakes for wear or damage.

    REPAIR as necessary.

  • INSPECT the drag link, inner and outer tie-rods or idler arm for wear or damage. REPAIR as necessary
  • INSPECT the upper and lower ball joints for wear or damage. REPAIR as necessary
  • CHECK for abnormal wheel bearing play or roughness.

    Refer to Wheel Bearing Check in this section.

    ADJUST or INSTALL new wheel bearings as necessary.
  • Clicking or snapping-occurs when accelerating around a corner
  • Damaged or worn outboard CV joint.
  • INSPECT the outboard CV joint and boot. REPAIR or INSTALL a new CV joint as necessary.
  • High pitched chattering-noise from the rear axle when the vehicle is turning
  • Incorrect or contaminated lubricant.
  • Damaged or worn differential (differential side gears and pinion gears).
  • 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
  • DISASSEMBLE the differential assembly.

    INSPECT the differential case, pin and gears for wear or damage. REPAIR or INSTALL a new differential as necessary
  • Buzz-buzzing noise is the same at cruise or coast/deceleration
  • Damaged or worn tires
  • Incorrect driveline angles
  • CHECK for abnormal tire wear or damage. INSTALL a new tire as necessary.
  • CHECK for correct driveline angles. REPAIR as necessary
  • 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 binding or seized.
  • Excessive pinion flange runout.
  • CHECK the driveshaft for damage, missing balance weights or undercoating.

    CHECK the driveshaft balance. CARRY OUT a driveline vibration test

  • ROTATE the driveshaft and CHECK for rough operation or seized U-joints. INSTALL new U-joints as necessary
  • CARRY OUT a runout check. REPAIR as necessary
  • Grunting-normally associated with a shudder experienced during acceleration from a dead stop
  • Driveshaft slip yoke binding.
  • Loose rear spring U-bolts.
  • CLEAN and LUBRICATE the male and female splines.
  • INSPECT the rear suspension. TIGHTEN the U-bolt nuts 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
  • CHECK the ring and pinion and bearings for damage.

    INSPECT the ring and pinion wear pattern. REFER to Checking Tooth Contact Pattern and Condition of the Ring and Pinion component test in this section. ADJUST or INSTALL new components as necessary.
  • Chuckle-heard at coast/deceleration.

    Also described as a knock
  • Incorrect ring and pinion contact or by damaged teeth on the coast side of the ring and pinion.
  • CHECK the ring and pinion for damage. INSPECT the ring and pinion wear pattern.

    REFER to Checking Tooth Contact Pattern and Condition of the Ring and Pinion component test in this section. ADJUST or INSTALL new components as necessary
  • Knock-noise occurs at various speeds.

    Not affected by acceleration or deceleration
  • Gear tooth damage to the drive side of the ring and pinion
  • Excessive axle shaft end play.(Vehicles with integral axles).
  • CHECK the differential case and ring and pinion for damage. INSTALL new components as necessary.
  • CHECK the axle end play using a dial indicator.

    INSTALL a new axle shaft or side gears as necessary.
  • Scraping noise-a continuous low pitched noise starting at low speeds
  • Worn or damaged pinion bearings.
  • CHECK the pinion bearings.

    INSTALL new pinion bearings as necessary.
  • Driveline shudder- occurs during acceleration from a slow speed or stop
  • Rear drive axle assembly mispositioned.
  • Loose rear spring U-bolts.
  • Incorrect or high CV joint operating angle
  • Damaged or worn front suspension components.
  • Driveline angles out of specification.
  • U-joints binding or seized.
  • Binding, damaged or galled splines on the driveshaft slip-yoke
  • CHECK the axle mounts and the rear suspension for damage or wear. REPAIR as necessary.
  • INSPECT the U-bolts.

    TIGHTEN the U-bolt nuts to specification

  • CHECK vehicle ride height is within limits. REPAIR as necessary.
  • CHECK for a loose stabilizer bar, damaged or loose strut/strut bushings or loose or worn ball joints. INSPECT the steering linkage for wear or damage. REPAIR or INSTALL new components as necessary.
  • CHECK for correct driveline angles. REPAIR as necessary
  • ROTATE the driveshaft and CHECK for rough operation or seized U-joints. INSTALL new U-joints as necessary.
  • CLEAN and INSPECT the splines of the slip-yoke, driveshaft and coupling shaft for a worn, damaged or galled condition.

    INSTALL a new slip-yoke or driveshaft assembly as necessary. REPAIR as necessary.
  • Driveline vibration- occurs at cruising speeds
  • U-joints are worn.
  • Worn or damaged driveshaft center bearing support
  • Loose axle pinion flange bolts.
  • Excessive axle pinion flange runout.
  • Driveshaft is out-of-balance.
  • Binding or damaged splines on the driveshaft slipyoke.
  • Driveshaft runout.
  • Incorrect lateral and radial tire/wheel runout.
  • Driveline angles out of specification.
  • Incorrectly seated CV joint in the front wheel hub.
  • CHECK for wear or incorrect seating. INSTALL new Ujoints as necessary
  • CHECK the insulator for damage or wear. ROTATE the driveshaft and CHECK for rough operation.

    INSTALL a new center bearing support as necessary

  • INSPECT the axle pinion flange. TIGHTEN the pinion flange bolts to specification.
  • CARRY OUT a Runout Check. REPAIR as necessary
  • CHECK the driveshaft for damage, missing balance weights or undercoating.

    CHECK driveshaft balance. CARRY OUT a driveline vibration test

  • CLEAN and INSPECT the splines of the slip-yoke, driveshaft and coupling shaft for wear or damage.

    INSTALL a new slip-yoke or driveshaft assembly as necessary.

  • CARRY OUT a Runout Check.
  • INSPECT the tire and wheels. MEASURE tire runouts. REPAIR or INSTALL new components as necessary.
  • CHECK for correct driveline angles. REPAIR as necessary
  • CHECK the outer CV joint for correct seating into the hub. REPAIR as necessary.

Symptom Chart - Engine Noise/Vibration

Condition Possible Sources Action
  • Grinding noise- occurs during engine cranking
  • Incorrect starter motor mounting.
  • Starter motor.
  • Incorrect starter motor drive engagement.
  • INSPECT the starter motor for correct mounting.

    REPAIR as necessary.

  • CHECK the starter motor.

    REPAIR or INSTALL a new starter motor as necessary.

  • INSPECT the starter motor drive and flexplate/flywheel for wear or damage.

    INSTALL a new starter motor drive or flywheel as necessary.
  • Engine ticking noise
  • Fuel injector.
  • Fuel line.
  • Oil pump.
  • Valve lifter.
  • Belt tensioner.
  • Water pump.
  • Obstruction of cooling fan.
  • Go To Pinpoint Test B .
  • Engine drumming noise-normally accompanied by vibration
  • Powertrain mount.
  • Damaged or misaligned exhaust system.
  • CARRY OUT Powertrain/Drivetrain Mount Neutralizing in this section.
  • INSPECT the exhaust system for loose or broken clamps and brackets.

    CARRY OUT Exhaust System Neutralizing in this section.
  • Whistling noise- normally accompanied with poor idle condition
  • Air intake system.
  • CHECK the air intake ducts, air cleaner, throttle body and vacuum hoses for leaks and correct fit.

    REPAIR or ADJUST as necessary.
  • Clunking noise
  • Water pump has excessive end play or imbalance.
  • Generator has excessive end play.
  • CHECK the water pump for excessive end play.

    INSPECT the water pump with the drive belt off for imbalance. INSTALL a new water pump as necessary.

  • CHECK the generator for excessive end play.

    REPAIR or INSTALL a new generator.
  • Pinging noise
  • Exhaust system leak.
  • Gasoline octane too low.
  • Knock sensor operation.
  • Incorrect spark timing.
  • High operating temperature.
  • Foul-out spark plug.
  • Catalytic converter.
  • INSPECT the exhaust system for leaks. REPAIR as necessary.
  • VERIFY with customer the type of gasoline used.

    CORRECT as necessary.

  • CHECK the knock sensor.

    INSTALL a new knock sensor as necessary.

  • CHECK the spark timing.

    REPAIR as necessary

  • INSPECT cooling system for leaks. CHECK the coolant level. REFILL as necessary. CHECK the coolant for the correct mix ratio. DRAIN and REFILL as needed. CHECK engine operating temperature is within specifications.

    REPAIR as necessary.

  • CHECK the spark plugs.

    REPAIR or INSTALL new spark plugs as necessary

  • Acceptable noise.
  • Knocking noise- light knocking noise, also described as piston slap. Noise is most noticeable when engine is cold with light to medium acceleration.

    Noise disappears as engine warms
  • Excessive clearance between the piston and the cylinder wall.
  • Engine cold and at high idle. Using an EngineEAR, pull a spark plug or fuel injector connector until the noise goes away. CARRY OUT a cylinder bore clearance to piston check.

    INSTALL a new piston
  • Knocking noise- light double knock or sharp rap sound.

    Occurs mostly with warm engine at idle or low speeds in DRIVE.

    Increases in relation to engine load. Associated with poor lubrication history
  • Excessive clearance between the piston and the piston pin.
  • INSTALL a new piston or piston pin.
  • Knocking noise- light knocking noise is most noticeable when engine is warm.

    Noise tends to decrease when vehicle is coasting or in neutral
  • Excessive clearance between the connecting rod bearings and the crankshaft.
  • Engine warm and at idle.

    Using an EngineEAR, PULL a spark plug or fuel injector connector until the noise goes away. INSTALL new bearings
  • Knocking-deep knocking noise.

    Noise is most noticeable when engine is warm, at lower rpm and under a light load and then at float
  • Worn or damaged crankshaft main bearings.
  • CARRY OUT DERU test.

    CHECK for noise with vehicle at operating temperature, during medium to heavy acceleration. CHECK at idle with injector disconnected, noise does not change. INSTALL new main bearings
  • Knocking noise- occurs mostly with warm engine at light/medium acceleration
  • Spark plugs.
  • Carbon accumulation in combustion chamber.
  • CHECK the spark plug for damage or wear. INSTALL new spark plugs as necessary.
  • REMOVE carbon from combustion chamber.
  • Whine or moaning noise
  • Air intake system.
  • Generator electrical field or bearings.
  • CHECK the air cleaner and ducts for correct fit.

    INSPECT the air intake system for leaks or damage. REPAIR as necessary.

  • CARRY OUT generator load test. REPAIR or INSTALL a new generator as necessary
  • Drone type noise
  • Exhaust system.
  • A/C compressor.
  • Powertrain mounts.
  • CARRY OUT the Exhaust System Neutralizing in this section. REPAIR as necessary.
  • CHECK for noise with vehicle at constant speeds.

    CYCLE the compressor on and off and listen for a change in pitch. REPAIR as necessary

  • CARRY OUT the Powertrain/Drivetrain Mount Neutralizing in this section
  • Sputter type noise-noise worse when cold, lessens or disappears when vehicle is at operating temperature
  • Damaged or worn exhaust system components.
  • INSPECT the exhaust system for leaks or damage. REPAIR as necessary
  • Rattling noise- noise from the upper engine (valve train)

    Worse when engine is cold
  • Low oil level.
  • Thin or diluted oil.
  • Low oil pressure.
  • Worn rocker arms/fulcrums or followers.
  • Worn valve guides.
  • Excessive runout of valve seats on the valve face.
  • CHECK oil level. FILL as necessary.
  • INSPECT the oil for contamination. If oil is contaminated, CHECK for the source. REPAIR as necessary. CHANGE the oil and filter.
  • CARRY OUT an oil pressure test. If not within specifications, REPAIR as necessary.
  • CARRY OUT a valve train analysis. INSTALL new valve train components as necessary
  • CARRY OUT a valve train analysis. INSTALL new valve guides as necessary.
  • CARRY OUT a valve seat runout test. INSPECT the valve face and seat.

    INSTALL new valves as necessary
  • Rattling noise- from the bottom of the vehicle
  • Loose muffler shields or catalytic converter shields.
  • CHECK the exhaust system for loose exhaust shields. REPAIR as necessary.
  • Thumping noise-from the bottom of the vehicle, worse at acceleration
  • Exhaust pipe/muffler grounded to chassis
  • CHECK the exhaust system to chassis clearance. CHECK the exhaust system hangers for damage. REPAIR as necessary
  • Whoosh-occurs during light vehicle acceleration.

    Heard inside the vehicle
  • Throttling late, creating turbulence transmitted through the plastic manifold.
  • CHECK for leaks or missing seal in the dash panel.
  • Engine vibration- increases intensity as engine rpm is increased
  • Engine out-ofbalance.
  • CARRY OUT Neutral Engine Run-Up (NERU) Test. ROTATE the torque converter, 120 for 3 bolt and 180 for 4 bolt.

    INSPECT the torque converter pilot outer diameter to crankshaft pilot inner diameter. REPAIR as necessary
  • Engine vibration-is felt with increases and decreases in engine rpm
  • Strain on exhaust mounts.
  • Damaged or worn powertrain/drivetrain mounts.
  • Engine or transmission grounded to chassis
  • CARRY OUT the Exhaust System Neutralizing procedure in this section.

    REPAIR as necessary

  • CHECK the powertrain/drivetrain mounts for damage.

    REPAIR as necessary.

  • INSPECT the powertrain/drivetrain for correct clearances.

    REPAIR as necessary
  • Engine vibration- vibration felt at all times
  • Excessive engine pulley runout.
  • Damaged or worn accessory component.
  • CARRY OUT Engine Accessory Test. INSTALL a new engine pulley as necessary
  • CARRY OUT Engine Accessory Test. REPAIR or INSTALL a new component as necessary.
  • Accelerator pedal vibration-felt through the pedal as a buzz
  • Throttle cable loose or misrouted.
  • INSPECT the throttle cable.

    REPAIR as necessary
  • Engine vibration-mostly at coast/neutral coast. Condition improves with vehicle accelerating
  • Combustion instability.
  • CHECK the ignition system.

    INSTALL new components as necessary.
  • Engine vibration or shudder- occurs with light to medium acceleration above 56 km/h (35 mph)
  • Worn or damaged spark plugs.
  • Plugged fuel injector
  • Damaged spark plug wire.
  • Contaminated fuel.
  • Worn or damaged torque converter.
  • INSPECT the spark plugs for cracks, high resistance or broken insulator.

    INSTALL a new spark plug (s) as necessary

  • REPAIR or INSTALL a new injector as necessary.
  • INSPECT the spark plug wires for damage. INSTALL a new spark plug wire(s) as necessary
  • INSPECT the fuel for contamination. DRAIN the fuel system and refill.
  • CHECK the torque converter. INSTALL a new torque converter as necessary

Symptom Chart-Idle Noise/Vibration

Condition Possible Sources Action
  • Idle air control (IAC) valve moan - occurs on throttle tip-out
  • IAC valve is contaminated with oil.
  • GO to Component Tests in this section.
  • Accessory drive belt chirp - occurs at idle or high idle, cold or hot. Most common occurrence is during humid weather
  • Accessory drive belt worn, or pulley is misaligned or loose.
  • INSPECT for loose or misaligned pulleys. CHECK the drive belt for wear or damage. INSTALL new pulley(s)/drive belt, or accessory drive components as necessary
  • Accessory drive bearing hoot - occurs at idle or high idle in cold temperatures of approximately +4C (+40F) or colder at first start of the day
  • Accessory drive idler or tensioner pulley bearing is experiencing stick/slip between ball bearings and bearing race.
  • Go To Pinpoint Test C .
  • Power steering moan - occurs at high idle and possibly at idle during the first cold start of the day in temperatures of approximately -18C (0F) or colder. Noise can even be a severe screech for less than one minute in very cold temperatures of approximately -29C (-20F) or colder
  • High fluid viscosity, or plugged reservoir screen in power steering reservoir starves pump causing cavitation.
  • Go To Pinpoint Test D .
  • Generator whine - during high electrical loads at idle or high idle, a high pitch whine or moan is emitted from the generator
  • Generator electrical field noise.
  • Using an EngineEAR, PROBE near the generator housing. LISTEN for changes in the noise level while changing electrical loads (such as rear defrost, headlamps, etc.). CARRY OUT a generator load test. If the system passes the load test, the noise is from the generator bearings, INSTALL new bearings. If the system fails the load test, INSTALL a new generator.
  • Engine-driven cooling fan moan - occurs during the first start of the day. It is most objectionable near idle speeds up to 2000 rpm. The noise increases with rpm
  • The viscous cooling fan clutch engages until the fluid in the clutch reaches normal operating temperature, causing the fan to fully engage.
  • Go To Pinpoint Test E .
  • Drumming noise - occurs inside the vehicle during idle or high idle, hot or cold.

    Very low-frequency drumming is very rpm dependent
  • Exhaust system vibration excites the body resonances inducing interior noise.
  • Engine vibration excites the body resonances inducing interior noise.
  • Go To Pinpoint Test F .
  • Hissing noise - occurs during idle or high idle that is apparent with the hood open
  • Vacuum leak or idle air control (IAC) valve flow noise.
  • Vehicles with a plastic intake manifold.
  • Use the Ultrasonic Leak Detector/EngineEAR to locate the source. Scan the air intake system from the inlet to each cylinder intake port. DISCARD the leaking parts, and INSTALL a new component.
  • Acceptable condition. Some plastic manifolds exhibit this noise, which is the effect of the plastic manifold.
  • Automatic transmission buzz or hiss
  • Incorrect driveline angles.
  • Worn or damaged main control solenoids or valves.
  • CHECK for correct driveline angles. REPAIR as necessary
  • Using a transmission tester, activate the solenoids to duplicate sound. INSTALL new components as necessary
  • Manual Transmission Clutch throw-out bearing whine. A change in noise pitch or loudness while depressing the clutch pedal
  • Worn throw-out bearing.
  • INSTALL a new throw-out bearing
  • Heating, vacuum and air conditioning (HVAC) system chirp - most audible inside the vehicle. Listen for a change in noise pitch or loudness while changing the HVAC system blower speed
  • Damaged or worn HVAC blower bearing
  • INSTALL a new blower motor
  • Air conditioning (A/C) clutch ticking - occurs when the compressor clutch engages
  • Acceptable noise.
  • Incorrect air gap.
  • LISTEN to the clutch to determine if the noise occurs with clutch engagement. A small amount of noise is acceptable. If the noise is excessive, CHECK the A/C clutch air gap. INSPECT the A/C clutch for wear or damage. INSTALL a new clutch as necessary
  • Intermittent rattle, or scraping/rubbing noise
  • Loose exhaust heat shield(s).
  • Wiring, hose or other part interfering with accessory drive belt or pulley.
  • INSPECT the exhaust system for loose parts using a glove or clamps to verify cause. REPAIR as necessary
  • INSPECT accessory drive system closely verifying there is adequate clearance to all rotating components.

    REPAIR as necessary.
  • Engine ticking or knocking noise - occurs during idle or high idle during the first cold start of the day
  • Piston noise or valvetrain noise (bled down lifter/lash adjuster).
  • Go To Pinpoint Test G .
  • A continuous, speeddependent rattle from the engine - occurs during idle or high idle during the first cold start of the day and disappears as the engine warms up
  • Piston noise or valvetrain noise (bled down lifter/lash adjuster).
  • Go To Pinpoint Test G .
  • Idle vibration-a lowfrequency vibration (5- 20 Hz) or mild shake that is felt through the seat/floorpan
  • Cylinder misfire
  • Engine or torque converter out of balance.
  • Using a scan tool, CHECK the ignition system. CARRY OUT a cylinder power test
  • VERIFY the torque converter to crankshaft pilot clearance is correct, REPAIR as necessary. REINDEX the torque converter on the flex plate by 120 on a 3 bolt converter or 180 for a 4 bolt converter
  • Idle vibration-a highfrequency vibration (20-80 Hz) or buzz, that is felt through the steering wheel or seat
  • Exhaust system mounts bound up.
  • Body mounts loose
  • Power steering lines grounded out.
  • VERIFY concern occurs at engine firing frequency.

    CHECK that the exhaust system vibrates at the same frequency as the engine.

    ADD 9-14 km (20-30 lb.) to the tail pipe to test, CARRY OUT Exhaust System Neutralizing in this section.

  • INSPECT the body mounts.

    REPAIR as necessary.

  • INSPECT that the power steering lines are not contacting the chassis or each other. REPAIR as necessary.

Symptom Chart-Squeak and Rattle

Condition Possible Sources Action
  • Squeak-heard inside the vehicle when closing/opening the door
  • Insufficient lubrication on the door hinge or check strap.
  • Internal door components loose, rubbing or misaligned.
  • LUBRICATE the hinge or check strap.
  • CHECK the inside of the door.

    TIGHTEN or ALIGN as necessary. USE the Rotunda Squeak and Rattle Kit to isolate any rubbing components.
  • Squeak-heard inside the vehicle when closing/opening the window
  • Worn or damaged glass run/channel.
  • REPAIR or INSTALL a new glass run/channel
  • Squeak-heard outside of vehicle when closing/opening the door
  • Exhaust shield rubbing against the chassis or exhaust pipe.
  • CHECK the exhaust system.

    REPAIR as necessary
  • Squeak-occurs with initial brake pedal application
  • Disc brake pads.
  • Under certain conditions, asbestos free pads can generate a squeak noise. This noise is normal and does not indicate a concern.
  • Squeak-a constant noise that occurs with brake pedal applications
  • Damaged or worn disc brake pads.
  • INSPECT the pads for oil, grease or brake fluid contamination. CHECK for glazed linings. A brake disc with hard spots will also cause a squeak type noise. REPAIR or INSTALL new pads as necessary
  • Squeak-noise occurs over bumps or when turning
  • Worn control arm bushings.
  • Worn or damaged shock absorber/strut.
  • INSPECT the control arm bushings. Spray with lubricant and CARRY OUT a "bounce test" to determine which bushing.
  • INSPECT the shock absorber for damage. CARRY OUT a "bounce test" to isolate the noise. INSTALL a new shock absorber/strut as necessary.
  • Rattle-heard when closing/opening the door or window
  • Loose internal door mechanism, bracket or attachment.
  • REPEAT the motion or CARRY OUT a "tap test" to duplicate the noise. INSPECT the door for loose components. TIGHTEN loose components or USE the Rotunda Squeak and Rattle Kit to isolate any rattling components.
  • Rattle - GT models only, noise occurs from the rear of the vehicle
  • A loose or under torqued shock damper attaching nut.
  • VERIFY the torque on the shock damper-to-axle nuts is 63 Nm (46 lb-ft). VERIFY the torque for the shock damper-torail bracket nuts is 90 Nm (66 lb-ft). Do not over torque.

    TIGHTEN as necessary
  • Squeak or rattle- heard inside the vehicle over rough roads/bumps
  • Misaligned glove compartment door/hinge.
  • Instrument panel trim loose or misaligned.
  • Loose interior component or trim.
  • ALIGN the glove compartment door.
  • INSPECT the instrument panel trim for missing or loose clips or screws. REPAIR as necessary.
  • CARRY OUT a "touch test".

    ELIMINATE the noise by pressing or pulling on interior trim and components. USE the Rotunda Squeak and Rattle Kit to isolate any rattling/squeaking components.
  • Squeak or rattle- noise with a vibration concern
  • Damaged or worn body mounts.
  • Damaged or worn sub-frame mounts.
  • INSPECT the upper and lower absorbers and washers for damage or wear. CHECK the body mount brackets for damage. CHECK the nuts and bolts are tightened to specifications. TIGHTEN as necessary.
  • INSPECT the upper and lower absorbers for damage or wear.

    CHECK the sub-frame for damage. CHECK the nuts and bolts are tightened to specifications. TIGHTEN as necessary.

Symptom Chart-Steering Noise/Vibration

Condition Possible Sources Action
  • Steering grunt or shudder - occurs when turning into or out of a turn at low speeds (temperature sensitive)
  • Steering gear or power steering hoses.
  • GO to Steering Gear Grunt/Shudder Test component test in this section.
  • Steering System clonk-hydraulic knocking sound
  • Air in the steering hydraulic system
  • CHECK for leaks in the system. PURGE the air from the system
  • Power steering pump moan - loud humming noise occurs when the steering wheel is rotated to the stop position.

    Produces a 120- 600 Hz frequency that changes with rpm
  • Power steering hose grounded out to chassis.
  • Aerated fluid.
  • Steering gear isolators.
  • Low fluid.
  • Power steering pump brackets loose or misaligned.
  • INSPECT the power steering hoses. REPAIR as necessary
  • CHECK for leaks in the system. PURGE the air from the system.
  • INSPECT the isolators for wear or damage.

    REPAIR as necessary

  • CHECK the fluid level. REFILL as necessary.
  • CHECK bolts, brackets and bracket alignment.

    TIGHTEN bolts to specification. REPAIR or INSTALL new brackets as necessary
  • Steering gear clunk - occurs only while cornering over a bump (can be temperature sensitive)
  • Steering gear.
  • INSPECT the steering gear for loose mounting bolts. TIGHTEN as necessary
  • Feedback (rattle, chuckle or knocking noise in the steering gear) - a condition where roughness is felt in the steering wheel when the vehicle is driven over rough surfaces
  • Column intermediate/flexible shaft joints damaged or worn.
  • Loose, damaged or worn tie-rod ends.
  • Steering gear insulators or mounting bolts loose or damaged.
  • Steering column intermediate shaft bolts are loose
  • Steering column damaged or worn
  • Loose suspension bushings, bolts or ball joints.
  • INSTALL a new intermediate/flexible shaft
  • TIGHTEN the nuts to specification or INSTALL new tie-rod ends as necessary
  • TIGHTEN the bolts or INSTALL new bolts as necessary
  • TIGHTEN the bolts to specification
  • REPAIR or INSTALL a new steering column as necessary
  • INSPECT the suspension system.

    TIGHTEN or INSTALL new components as necessary
  • Feedback (nibble at the steering wheel) - a condition where slight rotational movement is felt in the steering wheel when the vehicle is driven over rough or grooved surfaces
  • Lateral runout in the tire or wheel.
  • Yoke spring in the steering gear.
  • GO to Pinpoint Test H .
  • CHECK TSBs for revised yoke spring for applicable vehicles
  • Accessory drive belt squeal/chirp- when rotating the steering wheel from stop to stop
  • Loose or worn accessory drive belt.
  • ADJUST or INSTALL a new accessory belt as necessary
  • Power steering gear hiss
  • Steering column intermediate/flexible shaft-to-steering gear is binding or misaligned.
  • Grounded or loose steering column boot at the dash panel
  • Damaged or worn steering gear input shaft and valve.
  • REPAIR or INSTALL a new intermediate/flexible shaft as necessary
  • REPAIR as necessary.
  • REPAIR or INSTALL a new steering gear as necessary
  • Steering column rattle
  • Loose bolts or attaching brackets.
  • Loose, worn or insufficiently lubricated column bearings.
  • Steering shaft insulators damaged or worn
  • Intermediate/flexible shaft compressed or extended.
  • TIGHTEN the bolts to specifications
  • LUBRICATE or INSTALL new steering column bearings as necessary
  • INSTALL new insulators
  • INSPECT the rubber spider coupling for damage. INSTALL a new intermediate/flexible shaft.
  • Steering column squeak or cracks
  • Insufficient lubricated steering shaft bushings.
  • Loose or misaligned steering column shrouds
  • Steering wheel rubbing against steering column shrouds.
  • Insufficient lubricated speed control slip ring.
  • Upper or lower bearing sleeve out of position
  • LUBRICATE the steering shaft and shaft tube seals.
  • TIGHTEN or ALIGN the steering column shrouds.
  • REPOSITION the steering column shrouds
  • LUBRICATE the speed control slip ring.
  • REPOSITION the bearing sleeves
  • Power steering pump noisy
  • Incorrect assembly of components
  • Imperfections on the outside diameter or end surface of the power steering pump rotor.
  • Damaged or worn power steering pump rotor splines
  • A crack on the inner surface of the power steering pump cam.
  • Interference between the power steering pump rotor and cam.
  • Damaged or worn power steering pump rotor and pressure plates.
  • REPAIR or INSTALL a new power steering pump as necessary.
  • Power steering pump swish noise
  • Power steering fluid flow into the bypass valve of the pump valve housing with fluid temperature below 54 C (130F).
  • Acceptable condition.
  • Power steering pump whine noise
  • Aerated fluid.
  • Damaged power steering pump cam.
  • Damaged valve cover O-ring seal.
  • PURGE the air from the system.
  • REPAIR or INSTALL a new power steering pump as necessary
  • REPAIR or INSTALL a new power steering pump as necessary
  • Power steering pump clicking (mechanical) noise
  • Power steering pump rotor slippers too long, excessive rotor slipperto- slot clearance or damaged or worn rotor assembly.
  • REPAIR or INSTALL a new power steering pump as necessary.
  • Power steering pump clatter noise
  • Damaged corners on the outside diameter or the power steering rotor or distorted rotor slipper ring.
  • REPAIR or INSTALL a new power steering pump as necessary

Symptom Chart-Suspension Noise/Vibration

Condition Possible Sources Action
  • Squeak or grunt-noise from the front suspension, occurs more in cold ambient temperatures.

    More noticeable over rough roads or when turning

  • Clunk-noise from the front suspension, occurs in and out of turns
  • Front stabilizer bar insulators.
  • Loose front struts or shocks
  • Under these conditions, the noise is acceptable.

    CHECK TSBs.

  • INSPECT for loose nuts or bolts. TIGHTEN to specifications
  • Clunk-noise from the rear suspension, occurs when shifting from reverse to drive
  • Loose rear suspension components.
  • INSPECT for loose or damaged rear suspension components.

    REPAIR or INSTALL new components as necessary.
  • Click or pop-noise from the front suspension.

    More noticeable over rough roads or over bumps
  • Worn or damaged ball joints.
  • CARRY OUT a ball joint inspection. INSTALL new ball joints or control arms as necessary.
  • Click or pop (FWD vehicles)-noise occurs when vehicle is turning
  • Worn or damaged ball joints.
  • CARRY OUT a ball joint inspection. INSTALL new ball joints or control arms as necessary.
  • Click or snap-occurs when accelerating around a corner
  • Damaged or worn outboard CV joint.
  • INSPECT the outboard CV joint and boot.

    REPAIR or INSTALL a new CV joint as necessary.
  • Front suspension noise- a squeak, creak or rattle noise. Occurs mostly over bumps or rough roads
  • Steering components.
  • Loose or bent front struts or shock absorbers.
  • Damaged spring or spring mounts.
  • Damaged or worn control/radius arm bushings.
  • Worn or damaged stabilizer bar bushings or links.
  • Go To Pinpoint Test H .
  • Rear suspension noise- a squeak, creak or rattle noise. Occurs mostly over bumps or rough roads
  • Loose or bent rear shock absorbers.
  • Damaged spring or spring mounts.
  • Damaged or worn control arm bushings.
  • Worn or damaged stabilizer bar bushings or links.
  • Go To Pinpoint Test I .
  • Shudder-occurs during acceleration from a slow speed or stop
  • Rear drive axle assembly mispositioned.
  • Incorrect or high CV joint operating angle
  • Damaged or worn front suspension components.
  • CHECK the axle mounts and the rear suspension for damage or wear.

    REPAIR as necessary.

  • CHECK vehicle ride height is within limits.

    REPAIR as necessary.

  • CHECK for a loose stabilizer bar, damaged or loose strut/strut bushings or loose or worn ball joints.

    INSPECT the steering linkage for wear or damage. REPAIR or INSTALL new components as necessary.
  • Shimmy-most noticeable on coast/deceleration. Also hard steering condition
  • Excessive positive caster.
  • CHECK the caster alignment angle.

    CORRECT as necessary.

Symptom Chart-Tire Noise/Vibration

Condition Possible Sources Action
  • Tire noise-hum/moan at constant speeds
  • Abnormal wear patterns.
  • SPIN the tire and CHECK for tire wear. INSTALL a new tire as necessary.

    INSPECT for damaged/worn suspension components. CARRY OUT wheel alignment
  • Tire noise-noise tone lowers as the vehicle speed is lowered
  • Out-of-balance tire.
  • BALANCE the tire and road test. INSTALL a new tire as necessary
  • Tire noise - ticking noise, changes with speed
  • Nail puncture or stone in tire tread.
  • INSPECT the tire. REPAIR as necessary.
  • Wheel and tire- vibration and noise concern is directly related to vehicle speed and is not affected by acceleration, coasting or decelerating
  • Damaged or worn tire.
  • Go To Pinpoint Test J .
  • Tire wobble or shudder - occurs at lower speeds
  • Damaged wheel bearings.
  • Damaged wheel.
  • Damaged or worn suspension components.
  • Loose wheel nuts.
  • Damaged or uneven tire wear
  • SPIN the tire and CHECK for abnormal wheel bearing play or roughness.

    ADJUST or INSTALL new wheel bearings as necessary

  • INSPECT the wheel for damage. INSTALL a new wheel as necessary.
  • INSPECT the suspension components for wear or damage. REPAIR as necessary.
  • CHECK the wheel nuts.

    TIGHTEN to specification

  • SPIN the tire and CHECK for abnormal tire wear or damage. INSTALL a new tire as necessary
  • Tire shimmy or shake- occurs at lower speeds
  • Wheel/tire out of balance.
  • Uneven tire wear.
  • Excessive radial runout of wheel or tire.
  • Worn or damaged wheel studs or elongated stud holes.
  • Excessive lateral runout of the wheel or tire.
  • Foreign material between the brake disc and hub or in the brake disc fins
  • BALANCE the wheel/tire assembly.
  • CHECK for abnormal tire wear. INSTALL a new tire as necessary
  • CARRY OUT a radial runout test of the wheel and tire. INSTALL a new tire as necessary
  • INSPECT the wheel studs and wheels. INSTALL new components as necessary.
  • CARRY OUT a lateral runout test of the wheel and tire. CHECK the wheel, tire and hub.

    REPAIR or INSTALL new components as necessary.

  • CLEAN the mounting surfaces of the brake disc and hub. CHECK the brake disc fins for material.
  • High speed shake or shimmy-occurs at high speeds
  • Excessive wheel hub runout.
  • Damaged or worn tires.
  • Damaged or worn wheel bearings.
  • Worn or damaged suspension or steering linkage components.
  • Brake disc or drum imbalance.
  • Go To Pinpoint Test K .

Symptom Chart-Transmission (Manual) and Transfer Case Noise/Vibration

Condition Possible Sources Action
  • Clutch rattling noise- occurs with clutch engaged, noise changes/disappears with clutch pedal depressed
  • Flywheel bolts, clutch housing bolts or clutch pressure plate bolts loose.
  • TIGHTEN the bolts to specifications. CHECK the bolts for damage
  • Clutch squeaking noise-noise is heard when the clutch is operated. Vehicle moves slowly or creeps when the clutch is disengaged. Can also be difficult to shift into first and reverse gear
  • Pilot bearing seized or damaged
  • INSTALL a new pilot bearing
  • Clutch squeaking noise-occurs with clutch pedal depressed/released
  • Worn clutch pedal shaft or bushings.
  • INSPECT the clutch pedal for wear or damage. REPAIR as necessary
  • Clutch whirring/rattle noise-occurs when clutch pedal is depressed
  • Worn, damaged or misaligned clutch release bearing.
  • INSTALL a new clutch release bearing
  • Clutch grating/grinding noise-occurs when clutch pedal is depressed
  • Clutch pressure plate fingers bent or worn.
  • Contact surface of clutch release bearing worn or damaged.
  • INSPECT the clutch pressure plate release fingers. INSTALL a new pressure plate as necessary
  • INSTALL a new clutch release bearing.
  • Clutch chatter-a small amount of noise when clutch pedal is released at initial takeoff
  • Clutch engagement
  • Acceptable operating condition.
  • Clutch chatter/grabs- in some cases a shudder is felt. Occurs with clutch pedal depressed/released
  • Damaged or worn powertrain/driveline mounts.
  • Binding or dragging plunger of the clutch master cylinder or slave cylinder.
  • Grease or oil on the clutch disc facing.
  • Clutch disc surface glazed or damaged
  • Damaged or worn clutch pressure plate.
  • Flywheel surface damaged or glazed.
  • INSPECT the powertrain/drivetrain mounts. INSTALL new mounts as necessary
  • CHECK the master and slave cylinder operation. INSPECT the components for damage or wear.

    INSTALL a new master or slave cylinder as necessary.

  • CHECK the input shaft seal and rear main oil seal. REPAIR as necessary. INSTALL a new clutch disc.
  • INSPECT the clutch disc surface for a glazed, hardened or damage condition.

    CARRY OUT a disc check. INSTALL a new clutch disc as necessary.

  • INSPECT the clutch pressure plate for wear or damage. INSTALL a new clutch pressure plate as necessary.
  • INSPECT the flywheel for damage or wear.

    CARRY OUT a flywheel runout check.

    INSTALL a new flywheel as necessary.
  • Clutch chatter noise- noise when clutch pedal is released at initial take-off. Clutch is hard to engage and disengage
  • Pilot bearing worn, damaged or not correctly aligned in bore.
  • INSPECT the clutch pressure plate release fingers for uneven wear, clutch components burnt or a seized pilot bearing.

    INSTALL a new pilot bearing as necessary.
  • Clutch vibration
  • Loose flywheel bolts.
  • Damaged or loose clutch pressure plate.
  • Excessive flywheel runout.
  • Go To Pinpoint Test L .
  • Transmission rattling/clattering noise-noise at idle or on light acceleration from a stop. Gear selection difficult
  • Gearshift lever joint worn or damaged.
  • Gearshift lever loose.
  • Gearshift linkage rods worn or damaged.
  • INSTALL a new gearshift lever
  • TIGHTEN the bolts to specification.
  • CHECK the linkage bushings for wear.

    INSTALL new linkage rods as necessary.

    REFER to the appropriate workshop manual for the service procedures.
  • Transmission rattling/clattering noise-occurs in neutral or in gear, at idle
  • Incorrect fluid level or fluid quality
  • CHECK that the transmission is filled to the correct level and with the specified fluid
  • Transmission rattling/clattering noise-noise at idle in neutral
  • Worn or rough reverse idler gear.
  • Rough running engine, cylinder misfire.
  • Excessive backlash in gears
  • Worn countershaft gears.
  • CHECK the reverse idler gear. REPAIR as necessary.
  • CHECK the ignition system. CARRY OUT a cylinder power test.
  • CHECK the gear backlash. ADJUST as necessary
  • REPAIR as necessary.
  • Transmission whine- a mild whine at extreme speeds or high rpm
  • Rotating gears/geartrain.
  • Acceptable noise.
  • Transmission whine- a high pitched whine, also described as a squeal
  • Transmission gears are worn (high mileage vehicle).
  • Mismatched gear sets.
  • Damaged or worn transmission bearing.
  • Result of normal gear wear. REPAIR as necessary
  • INSPECT the gear sets for an uneven wear pattern on the face of the gear teeth. REPAIR as necessary
  • INSPECT the transmission bearings.

    INSTALL new bearings as necessary
  • Transmission growling/humming- noise occurs in the forward gears. The noise is more prominent when the gear is loaded. The problem gear can be located as the noise occurs in a specific gear position
  • Gear is cracked, chipped or rough.
  • INSPECT the transmission gears for damage or wear.

    INSTALL new gears as necessary
  • Transmission hissing-noise in neutral or in forward gears. As bearings wear or break up, the noise changes to a thumping noise
  • Damaged or worn bearings.
  • INSPECT the transmission bearings.

    INSTALL new bearings as necessary
  • Transmission knocking/thudding- noise at low speeds in forward gears
  • Bearings with damaged balls or rollers or with pitted and spalled races.
  • INSPECT the transmission bearings.

    INSTALL new bearings as necessary
  • Transmission rumble/growl-noise at higher speeds in forward gears, more pronounced in a coast/deceleration condition
  • Incorrect driveline angle
  • Driveshaft out of balance or damaged.
  • CHECK the driveline angle. REPAIR as necessary.
  • CHECK the driveshaft for damage, missing balance weights or undercoating. Using the vibration analyzer (VA), CHECK the driveshaft balance. CARRY OUT a driveline vibration test. For additional nformation
  • Transmission rumble/growl-noise at all speeds in forward gears, more pronounced in a heavy acceleration condition
  • Damaged or worn transmission bearing or gears (high mileage vehicles).
  • CHECK transmission fluid for excessive metal particles.

    REPAIR as necessary.
  • Transfer case whine- noise at all ranges
  • Incorrect fluid level or fluid quality.
  • Worn oil pump.
  • Under-inflated or oversized tires.
  • CHECK that the transfer case is filled to the correct level and with the specified fluid.
  • DISASSEMBLE the transfer case. CHECK the oil pump for wear or damage. REPAIR as necessary.
  • CONFIRM that the tires and wheels are correct for the vehicle. CHECK that the tire inflation pressures are correct.
  • Transfer case growl/rumble-noise at all ranges (A small amount of planetary noise can be heard when the transfer case is operated in low range.)
  • Damaged or worn bearings or planetary gear.
  • DISASSEMBLE the transfer case. CHECK the bearings or planetary gear for wear or damage. REPAIR as necessary.
  • Transfer case scraping/grating- noise at all ranges
  • Excessively stretched drive chain hitting the case.
  • DISASSEMBLE the transfer case. CHECK the drive chain for wear or damage. REPAIR as necessary.
  • Transfer case howl/hum-noise at all ranges or high range only
  • Worn or damaged sun (input) gear, clutch pack (intermediate) gear or output shaft gear.
  • DISASSEMBLE the transfer case. CHECK the gears for wear or damage. REPAIR as necessary.
  • Transfer case howl/hum-noise at low range only
  • Worn or damaged intermediate gear and sliding gears (clutch pack).
  • DISASSEMBLE the transfer case. CHECK the gears for wear or damage. REPAIR as necessary.
  • Transfer case vibration-vibration felt with vehicle in 4WD
  • Transfer case mounting.
  • Driveshaft out of balance.
  • Excessive pinion flange runout.
  • Go To Pinpoint Test M .

Symptom Chart-Transmission (Automatic) Noise/Vibration

Condition Possible Sources Action
  • Rattle-occurs at idle or at light acceleration from a stop
  • Damaged engine or transmission mounts.
  • A loose front exhaust pipe heat shield
  • Loose inspection plate or dust cover plate
  • Loose flex plate to converter nuts.
  • CHECK the powertrain/drivetrain mounts for damage. REPAIR or INSTALL new mounts as necessary
  • REPAIR or INSTALL a new heat shield as necessary
  • CHECK for loose bolts.

    TIGHTEN to specifications

  • CHECK for loose nuts.

    TIGHTEN to specifications.
  • Whine-pitch increases with vehicle speed.

    Starts in first and second gear, decreases or goes away at higher gears
  • Damaged or worn low one-way clutch.
  • Damaged or worn intermediate one-way clutch.
  • Friction elements.
  • Damaged or worn planetary or sun gear
  • INSPECT the transmission for wear or damage. REPAIR or INSTALL new components as necessary
  • Whine-the pitch changes with engine speed
  • A worn or damaged accessory drive component.
  • Incorrect fluid level.
  • Partially blocked filter
  • Worn or damaged torque converter.
  • Worn or damaged front pump.
  • CARRY OUT the Engine Accessory Test. REPAIR or INSTALL new components as necessary
  • CHECK that the transmission is filled to the correct level.

    ADD fluid as necessary.

  • INSPECT the filter. CLEAN or INSTALL a new filter as necessary
  • CARRY OUT the torque converter service and replacement check
  • INSPECT the front pump.

    INSTALL a new front pump as necessary
  • Whine-pitch changes with vehicle speed
  • Speedometer cable or gears
  • REPAIR or INSTALL new cables or gears as necessary
  • Whine/moan type noise- pitch increases or changes with vehicle speed
  • Damaged engine or transmission mount
  • U-joints worn or damaged.
  • Damaged or worn differential ring and pinion.
  • Planetary gears nicked or chipped.
  • CHECK the powertrain/drivetrain mounts for damage. CARRY OUT Powertrain/Drivetrain Mount Neutralizing in this section.
  • INSPECT the U-joints for wear or damage. INSTALL new U-joints as necessary
  • INSPECT the differential ring and pinion for damage.

    CARRY OUT the Checking Tooth Contact Pattern and Condition of the Ring and Pinion component test in this section. REPAIR or INSTALL a new differential ring and pinion as necessary.

  • CHECK the planetary gears for damage. INSTALL new components as necessary.
  • Whistle-noise is high pitched, constant.

    Changes in pitch with throttle position
  • Hydraulic pressure in the main control.
  • Incorrect band/clutch apply pressure.
  • Worn or damaged torque converter.
  • INSPECT the main control.

    REPAIR or INSTALL new components as necessary.

  • CARRY OUT the line pressure tests. REPAIR or INSTALL components as necessary.
  • CARRY OUT the torque converter service and replacement check
  • Clunk-occurs when shifting from PARK to a drive or reverse position
  • Bump-occurs when shifting from PARK to a drive or reverse position.

    Similar to Clunk but with no sound
  • Damaged powertrain mounts.
  • Damaged or worn pinion bearings.
  • Worn or galled driveshaft slip yoke splines.
  • Worn friction elements or excessive clutch pack end plate play.
  • Initial gear engagement
  • INSPECT the powertrain mounts for damage. INSTALL new mounts as necessary.
  • CHECK for abnormal bearing play or roughness. INSTALL new bearings as necessary.
  • CLEAN and INSPECT the splines of the yoke. INSTALL a new slip yoke as necessary
  • INSPECT the transmission for wear. CHECK that all end play and clearances are within specification. REPAIR or INSTALL new components as necessary
  • Acceptable condition.
  • Buzz or hiss
  • Incorrect driveline angles.
  • Worn or damaged main control solenoids or valves.
  • CHECK for correct driveline angles. REPAIR as necessary.
  • Using a transmission tester, ACTIVATE the solenoids to duplicate sound. INSTALL new components as necessary.
  • Vibration-a high frequency (20-80 Hz) that is felt through the seat or gear shifter.

    Changes with engine speed
  • Transmission cooler lines grounded out.
  • Flexplate to torque converter nuts loose.
  • Fluid filler tube grounded out.
  • Shift cable incorrectly routed, grounded out or loose.
  • CHECK the transmission cooler lines. REPAIR as necessary.
  • CHECK the flexplate nuts.

    TIGHTEN to specification.

  • CHECK the fluid filler tube.

    REPAIR as necessary.

  • CHECK the shift cable.

    REPAIR as necessary.
  • Shutter or chatter- occurs with light to medium acceleration from low speeds or a stop
  • Electrical inputs/outputs.
  • Vehicle wiring harness.
  • Incorrect inputs/outputs from the powertrain control module (PCM), digital transmission range (TR) sensor, brake pedal position (BPP) sensor, throttle position (TP) sensor, transmission speed sensor (TSS), output speed shaft (OSS) sensor or the torque converter clutch (TCC).
  • CARRY OUT a Torque Converter Clutch Operation Test. RUN on-board diagnostics or self-test. CLEAR the DTC's, ROAD TEST and RERUN on-board diagnostics or self-test.
    NVH Condition and Symptom Categories
    A good diagnostic process is a logical sequence of steps that lead to the identification of a causal system. Use the condition and symptom categories as follows: Identify the operating condition th ...

    Pinpoint Tests
    The pinpoint tests are a step-by-step diagnostic process designed to determine the cause of a condition. It may not always be necessary to follow a pinpoint test to its conclusion. Carry out only th ...

    Other materials:

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