Whining Noise From The Rear Of The Car
A whine or howl from the back of a rear- or four-wheel-drive car that changes with speed and with accelerating or lifting off often comes from the differential; a rear wheel bearing can sound similar.
Normal risk
Usually not urgent, but have it checked soon. A differential that runs low on oil can wear quickly and eventually seize.
Short answer · Why does my car whine from the back?
On cars that drive the rear wheels, the differential turns the drive through 90 degrees using gears. When the oil is low or old, or the gears and bearings wear, they whine. The noise typically changes when you accelerate, cruise or lift off. A rear wheel bearing hums with speed but does not change with throttle.
Safe checks you can do
- Notice if throttle changes itA whine that appears only when accelerating or only when lifting off points to the differential gears.
- Look for oil under the rear axleWet patches or drips around the differential housing mean the oil level may be low.
- Compare with engine speedIf the noise follows road speed but not engine revs, it is in the driveline, not the engine.
Questions that narrow it down
- Is the car rear- or four-wheel drive?Front-wheel-drive cars have no rear differential.
- Does it change between accelerating and coasting?Typical of worn differential gears.
- Is it louder in corners?Points more to a wheel bearing.
Possible causes
Listed without ranking. Use the questions above to see which ones fit your car.
- Low or old differential oilThe gears run dry and whine.
- Worn differential bearingsA howl that grows with speed.
- Worn crown wheel and pinionWhine on load or on overrun.
- Rear wheel bearingHum that changes in corners, not with throttle.
Questions about Whining Noise From The Rear Of The Car
How often is differential oil changed?
It depends on the car; many service schedules give a mileage or say it is filled for life. Check the maintenance schedule.
Can I keep driving with a whining differential?
Usually for a while, but have the oil level checked first. A noise that suddenly gets louder or turns into a grind needs attention right away.