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Quick Guide to Diagnosing Differential & Driveline Noises

 

Differential

We don’t know which sounds worse—car guys singing show tunes in the shower or a howling differential. While there is no help for our singing, we can help you diagnose the sounds coming from a differential gone bad.

A clunk, whine, or howl can signal a worn-out pinion gear, bad bearings, or a faulty gear installation. Sometimes, the noise is not differential-related, but is caused by other driveline or axle components. This guide will help you match up the noise you’re hearing with the differential or axle component making it, or at least get you in the ballpark.

Noise: Howl while decelerating (gears previously quiet)
Cause: Loose pinion bearing preload

Noise: Howl with whir or rumble while accelerating at any speed (gears previously quiet)
Cause: Worn rear pinion bearing or worn gear set

Noise: Howl without whir or rumble while accelerating at any speed (gears previously quiet)
Cause: Worn gear set due to lack of lubrication or overloading

Noise: Howling while accelerating over a small speed range (gears previously quiet)
Cause: Worn gear set due to lack of lubrication or overloading

Noise: Howling after gear set installation
Cause: Faulty gears or improper installation

Noise: Low-pitch rumble at all speeds over 20 miles per hour
Cause: Worn carrier bearings

Noise: Whirring during acceleration/deceleration at about 10 miles per hour
Cause: Worn pinion bearings

Noise: Banging or clunking while making a turn, backing up, or rapid deceleration (like on a freeway off-ramp). Noise gets worse in warmer weather
Cause: Posi chatter due to improper lubrication; worn clutches or spider gears; improper assembly

Noise: Banging, crunching, or popping while making a turn. Noise not affected by temperature
Cause: Badly worn or broken spider gears

Noise: Banging or heavy clicking every two to three feet during acceleration and deceleration
Cause: Damaged or broken pinion gear tooth or teeth

Noise: Banging or heavy clicking every two to three feet during acceleration or deceleration, but not both
Cause: High spot or heavy chip on pinion gear tooth

Noise: Banging or heavy clicking every eight feet during acceleration and deceleration
Cause: Damaged or broken ring gear tooth or teeth

Noise: Banging or heavy clicking every eight feet during acceleration or deceleration, but not both
Cause: High spot or heavy chip on ring gear tooth

Noise: Clicking while decelerating from 20 miles per hour to a complete stop
Cause: Worn carrier case-side gear bores

Noise: Rumble or clicking that gets worse during hard turns
Cause: Bad wheel bearings

Noise: Driveline squeaking or grinding at any speed
Cause: Worn or damaged U-joints

Noise: Clunking when depressing the throttle pedal (takeoff)
Cause: Worn U-joints; worn spider gears; worn axle splines; excessive gear backlash; loose yoke splines; worn slip yoke splines

Noise: Clunk immediately after taking off from a stop
Cause: Worn slip yoke splines

Noise: Steady vibration that increases with speed
Cause: Worn U-joint or out-of-balance driveshaft

Noise: Cyclic vibration that varies in intensity. Intensity increases at a specific speed range, worsens during deceleration
Cause: Pinion angle too low (not parallel with front yoke on driveshaft)

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17 Comments

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  3. clanging or rattling at rearend yoke on 1979 f-100 4×4;comes and goes

  4. Nice write up,
    I would like to include the (TC) transfer case to this board
    I experienced a sudden breakage when a loud burring grinding noise came from TC while accelerating thru first 2-3 gears under light load, avoidable by creeping slowly up to speed
    Engagement of 4WD eliminated the noise, except sometimes in reverse
    My 1997 K1500 had blown its TCs rear retainer snap ring on its NP243 (NP241) new proscess transfer case

    It is accessable by removing rear driveshaft (4 bolts at U-joint 12mm) and then removing rear cover of transfer case (four 15mm bolts) while still in vehicle

    You may want to empty TC fluid first to check fluid for metal shavings, or just expect a small amount to come out of back housing

    You should see remainder of snap ring in there, stock replacement at GM runs 8 dollars or beefy upgrade part (“TC Saver”) around 50 online ( I have broken two stock rings…)

    You may need snap ring reverse pliers to install stock option but not needed for TC saver

    Good time to clean and lubricate driveshaft and bearings. I believe a sticky spline on driveshaft contributes to this common breakage

  5. charles neilson says:

    I have a 2013 370Z Coupe which has been howling in a cyclic manner most notably around 60 to 80 mph. It sounds like Ooooooooohhhhhh…..pause…..Ooooooooohhhhhhhh……pause Oooooooohhhhhh. It’s pitch correlates to tire speed and not rpms. Just previous to this noise starting up, I ran over some round stone markers that divide the street from a metro railway in downtown Houston which I never saw while sitting in this low car (it was at night). I felt a nasty bump-bump-bump-bump before I pulled off these dividers. I checked my affected tire (left front) and found a visible bubble (“aneurysm”) and put new tires on both fronts as they were needed. But driving on freeway, that ghost-like howling was noticeable (and I wear hearing aids). There was no steering wheel rumble/vibtrations at different speeds. I thought about wheel bearings but the tires were tight but I found two 1 and 1/2 inch rim bangs only one of which was obvious. I took a one pound rubber mallet and brought the rims closer to the tire but definitely not perfect looking on one of the two sites. The howling persisted. I just got the left front wheel straightened and the wheel looks perfect again…….and the howling is gone. In fact it was gone when I put another wheel on the left front while I waited for my wheel. For the life of me, I can’t figure out why this Ray’s 19inch forged Nismo styled 2013 wheel would make a cyclic ghost-like howling down the highway….but it did. I think that is the end of the problem. Chazz46

  6. Major Flewellyn says:

    I believe I have a “Worn gear set due to lack of lubrication or overloading” issue. Do you think me checking for low differential oil, and if low, then draining fluid and replacing with new fluid will fix this problem? Or would I still have to take apart the differential and possibly replace parts?

    Thanks, Any information is appreciated.

    • OnAllCylinders says:

      Checking & changing the fluid is a great idea. Also, while you have the rear cover off you can inspect the gear set for discoloration due to low fluid and any abnormal wear patterns. If this exists, an overhaul is suggested before it lets you down. If there is no noise and no signs of wear or discoloration, fix the leak and refill with fresh gear oil.

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