Differential and Issues


What is a differential and why is it important?

There are quite a few folks around us who like to take their car to the mountains, racetracks, etc. only to enjoy the way their car handles around corners. For that purpose, they utilize different kind of cars, the kind that have the necessary go-fast goodies to ensure they can go fast on straights or turns. Such cars come equipped with what you call a differential. What a differential does is it keeps a check on the car’s tires when it is going around the corners. When a car starts turning, usually the inside tires spin as much as the outer tires, making the car lose its balance around corners. A differential stops this by making the inner tires spin less than the outer ones to ensure the vehicle retains its balance throughout the corner. You may ask why and the answer is simple. The inner tires have to travel less and should be engaged more in turning the car around. On the other hand, the outer tires have to travel more distance to keep up with inner tires and hence, have to spin faster. A differential helps manage the rotational forces between tires. The type of differential your car has depends on whether it is a front wheel drive, rear wheel drive or all wheel drive. The differential combines the working of gears, shafts, pinion, wheels, bearings, axle etc. Usually sounds like a clunk, whine or howl may indicate bad bearings, worn out pinion gear or an imperfect gear installation. Noises may also be caused by axle or other driveline components. So, here is a guide about how you can spot a differential issue.

What are the symptoms of differential and driveline issues?

  • If gears were previously quiet but you hear a howl while decelerating, it may be due to loose pinion bearing preload.
  • Gears were previously quiet but you hear a howl with rumble or whir while accelerating at any speed. Probably the cause is worn rear pinion bearing or worn gear set.
  • Gears were previously quiet but you hear a howl without rumble or whir while accelerating at any speed. This may be due to worn gear set which is overloaded or lacks lubrication.
  • Do you hear howling while accelerating over a small speed range despite previously quiet gears? Again worn gear set lacking lubrication or suffering from overload may be the reason.
  • Howling after gear set installation signifies faulty gears or improper installation.
  • Low pitch rumble at all speeds greater than 32kms / hr, is due to worn carrier bearings.
  • Whir heard during deceleration or acceleration at around 16kms/hr, may be due to worn pinion bearings.
  • Banging or clanking while turning, backing up or rapid deceleration, can be caused by worn clutches or spider gears, improper lubrication, or defective assembly.
  • If you hear banging or heavy clicking every 2 – 3 feet while accelerating and decelerating, then the cause may be damaged or broken pinion gear teeth.
  • If you hear banging or heavy clicking after about every 8 feet while accelerating and decelerating, then the cause may be broken or damaged ring gear teeth.
  • Do you hear rumble or clicking that worsens during hard turns? It may be because of bad wheel bearings.
  • Driveline squeaking or grinding irrespective of speed may be due to damaged or worn U joints.
  • Clunking sound when you press the throttle pedal for takeoff may have several reasons like, worn U joints or spider gears, worn axle splines, extreme gear backlash, loose yoke splines or worn out slip yoke splines.
  • If you hear a clunk right after taking off from a stop, worn slip yoke splines may be the issue.
  • Steady vibration that rises with speed may be caused by worn U joint or a driveshaft that is out of balance.

For any of the above symptoms, please get in touch with a professional and reputed automotive repair shop for detailed inspection.

Look out for these too

Lubrication and cooling of your car’s differential is necessary for smooth operation. The differential fluid or oil protects the metal surfaces of the gears from friction, thereby preventing overheating or burning. Ask a mechanic to check the differential oil during a regular maintenance service. If it is contaminated with metal particles or other substances, the oil has to be changed.


Differential problems can produce highly irritating noises and affect the smooth functioning of your car, especially during turns. So watch out for the various abnormal sounds that were discussed in this article. We at CarDekho would be happy to help you in efficiently resolving the differential issues of your car. Simply log on to services.cardekho.com to avail our inspection services and cost estimates.