Symptom Chart - NVH
WARNING: This page is about a different car, the 2017 Ford Expedition. However, it is still accessible from the selected car via links, so may be relevant.
| Condition | Possible Sources | Action |
|---|---|---|
|
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 and 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 and Harshness
for the next likely system and continue diagnosis.
|
||
| Axle howling or whine - front or rear axle | Axle lubricant low | CHECK the lubricant level. FILL the axle to specification. REFER to Rear Drive Axle/Differential - Ford 9.75-Inch Ring Gear or Front Drive Axle/Differential . |
| Axle housing damage | INSPECT the axle housing for damage. REPAIR or INSTALL a new axle as necessary. REFER to Rear Drive Axle/Differential - Ford 9.75-Inch Ring Gear or Front Drive Axle/Differential . | |
| Damaged or worn wheel hub bearings | CHECK for abnormal wheel hub bearing play or roughness. REFER to Front Suspension Rear Wheel Drive (RWD) , Front Suspension Four Wheel Drive (4WD) or Rear Suspension . | |
| Damaged or worn differential ring and pinion | INSPECT and INSTALL a new differential ring and pinion as necessary. REFER to Rear Drive Axle/Differential - Ford 9.75-Inch Ring Gear or Front Drive Axle/Differential . | |
| Damaged or worn differential side or pinion bearings | INSPECT and INSTALL new differential side or pinion bearings as necessary. REFER to Rear Drive Axle/Differential - Ford 9.75-Inch Ring Gear or Front Drive Axle/Differential . | |
| Driveline clunk - loud clunk when shifting from REVERSE to DRIVE | Incorrect axle lubricant level | CHECK the lubricant level. FILL the axle to specification. REFER to Rear Drive Axle/Differential - Ford 9.75-Inch Ring Gear or Front Drive Axle/Differential . |
| Excessive backlash in the axle | CHECK the axle backlash. REPAIR as necessary. REFER to Rear Drive Axle/Differential - Ford 9.75-Inch Ring Gear or Front Drive Axle/Differential . | |
| Damaged or worn pinion bearings | REPAIR or INSTALL new pinion bearings as necessary. REFER to Rear Drive Axle/Differential - Ford 9.75-Inch Ring Gear or Front Drive Axle/Differential . | |
| Damaged or worn U-joints | INSPECT the U-joints for wear or damage. INSTALL new U-joints or driveshaft 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 axle mount | CHECK the axle for loose bolts. TIGHTEN to specification. REFER to Rear Drive Axle/Differential - Ford 9.75-Inch Ring Gear or Front Drive Axle/Differential . | |
| Driveline clunk - occurs during acceleration or from cruise to coast/deceleration | Damaged or worn CV joint | INSPECT the CV joint and boot. INSTALL a new CV joint as necessary. REFER to Front Drive Halfshafts or Rear Drive Halfshafts . |
| 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 Front Drive Halfshafts or Rear Drive Halfshafts . |
| Another component contacting the halfshaft | CHECK the halfshafts and the area around the halfshafts. REPAIR as necessary. | |
| 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 the axle to Specification. REFER to Rear Drive Axle/Differential - Ford 9.75-Inch Ring Gear or Front Drive Axle/Differential . |
| Damaged or worn differential (differential side gears and pinion gears) | REPAIR or INSTALL new differential side gears or pinion gears as necessary. REFER to Rear Drive Axle/Differential - Ford 9.75-Inch Ring Gear or Front Drive Axle/Differential . | |
| Buzz - buzzing noise is the same at cruise or coast/deceleration | Incorrect driveline angles | CHECK for correct driveline angles. REPAIR as necessary. REFER to Driveline Angle Measurement . |
| 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 | CHECK the driveshaft for damage, missing balance weights or undercoating. REFER to Driveshaft Runout and Balancing . |
| 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 . | |
| Grunting - normally associated with a shudder experienced during acceleration from a complete stop | Driveshaft CV joint binding | CLEAN the CV joint and INSTALL a new driveshaft as necessary. REFER to Driveshaft . |
| Loose axle mount bolts or suspension fasteners | INSPECT the rear suspension and axle. TIGHTEN the fasteners to specification. REFER to Rear Drive Axle/Differential - Ford 9.75-Inch Ring Gear or Front Drive Axle/Differential . | |
| 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 | INSPECT and REPAIR as necessary. REFER to Rear Drive Axle/Differential - Ford 9.75-Inch Ring Gear or Front Drive Axle/Differential . |
| 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 | INSPECT and REPAIR as necessary. REFER to Rear Drive Axle/Differential - Ford 9.75-Inch Ring Gear or Front Drive Axle/Differential . |
| Knock - noise occurs at various speeds. Not affected by acceleration or deceleration | Gear tooth damage to the drive side of the ring and pinion | INSTALL a new ring and pinion. REFER to Rear Drive Axle/Differential - Ford 9.75-Inch Ring Gear or Front Drive Axle/Differential . |
| Scraping noise - a continuous low pitched noise starting at low speeds | Worn or damaged pinion bearings | INSPECT and REPAIR or INSTALL new pinion bearings. REFER to Rear Drive Axle/Differential - Ford 9.75-Inch Ring Gear or Front Drive Axle/Differential . |
| Driveline shudder - occurs during acceleration from a slow speed or stop | Drive axle assembly mispositioned | CHECK the axle mounts and the rear suspension for damage or wear. REPAIR as necessary. REFER to Rear Drive Axle/Differential - Ford 9.75-Inch Ring Gear or Front Drive Axle/Differential . |
| Loose axle bolts | CHECK the axle for loose bolts. TIGHTEN the bolts to specification. REFER to Rear Drive Axle/Differential - Ford 9.75-Inch Ring Gear or Front Drive Axle/Differential . | |
| Driveline angles out of specification | CHECK for correct driveline angles. REFER to Driveline Angle Measurement . | |
| 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 . | |
| 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 . | |
| Transfer case | REFER to Four Wheel Drive (4WD) Systems . | |
| 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 . |
| 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 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 | CARRY OUT a Pinion Flange Runout Check. REPAIR as necessary. REFER to Pinion Flange Runout Check. | |
| 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 | CARRY OUT a runout check. REFER to Driveshaft Runout and Balancing . | |
| Driveline angles out of specification | CHECK for correct driveline angles. REPAIR as necessary. REFER to Driveline Angle Measurement . | |
| Incorrectly seated CV joint in the wheel hub | CHECK the outer CV joint for correct seating into the hub. REPAIR as necessary. REFER to Front Drive Halfshafts for the front CV joints or Rear Drive Halfshafts for the rear CV joints. | |
Axle Fluid Analysis
The appearance of milky or gray axle fluid in early mileage axles is a result of white marking compound used at the assembly plant to verify gear mesh contact pattern. The marking compound within the fluid will darken some over time. The milky fluid appearance will diminish and cause no harm and does not require a fluid change.
Analysis of Leakage
Clean up the leaking area enough to identify the exact source.
A plugged axle housing vent can cause excessive pinion seal lip wear due to internal pressure buildup.
Verify the lubricant level is at least 3-5 mm (1/8-3/16 in) below the bottom of the fill hole.
Axle Vent
A plugged vent will cause excessive seal lip wear due to internal pressure buildup. If a leak occurs, check the vent. If the vent cannot be cleared, install a new vent.
Drive Pinion Seal
Leaks at the drive pinion seal originate from the following causes:
- Damaged seal
- Worn seal journal surface
Any damage to the seal bore (dings, dents, gouges or other imperfections) distorts the seal casing and allows leakage past the outer edge of the drive pinion seal.
The drive pinion seal can be torn, cut or gouged if it is not installed correctly. The spring that holds the drive pinion seal against the pinion flange may be knocked out and allow fluid to pass the lip.
Metal chips trapped at the sealing lip can cause oil leaks. These can cause a wear groove on the drive pinion flange and result in pinion seal wear.
When a seal leak occurs, install a new drive pinion seal and check the vent to make sure it is clean and free of foreign material.
A new drive pinion flange must be installed if any of these conditions exist.
Drive Pinion Nut
NOTE:
Install the drive pinion nut to the correct torque specifications or damage to the differential components may occur.
On some high-mileage vehicles, oil may leak through the threads of the drive pinion nut. This condition can be corrected by installing a new nut and clean the pinion nut mating surface of the pinion flange.
Differential Seals
NOTE:
When installing shafts, do not allow splines to contact seals during installation or damage to the seals may occur.
Halfshaft pilot bearing housing seals are susceptible to the same types of damage as drive pinion seals if incorrectly installed. The seal bore must be clean and the lip handled carefully to avoid cutting or tearing it. The seal journal surface must be free of nicks, gouges and rough surface texture.
For information on differential seals, refer to Rear Drive Axle/Differential - Ford 9.75-Inch Ring Gear .