Strange sound

I have a 2001 Subaru Forester with 93,000 miles. I have had it serviced faithfully every 3,000 miles, following the manufacturer’s suggested maintenance schedule. I have also replaced the timing belt recently. I am hearing a strange whining sound coming from the engine which starts when I reach 30 mph and gets louder as I accelerate. Any suggestions?

If you rev the engine in neutral, do you still hear the sound? Or do you have to be driving?

No, it’s only when I am driving.

I’m assuming this car has an automatic transmission.

Check the oil level in the front differential. The owner’s manual should have a diagram for this.

If the noise only occurs while driving it may not be coming from the engine, but from something in the drive train instead.

thank you. I will do that.

I’m sorry, it is a manual transmission…

Check the level of oil in the transmission. I think the front differential shares oil with the transmission on this car. The automatic cars have a separate differential.

thank you!

Kay, Without Being Able To Hear It, I Wouldn’t Rule Out A Worn Wheel Bearing. They Usually Make A sound That Can Increase With Vehicle Speed.

Is it a high pitched sound or a lower pitched sound ? Could you describe it as a high pitched squeal or zzzinging sound ? Could you describe it as almost a growling or grinding sound ?

Have you noticed if the sound can be changed (louder, quieter, higher / lower pitch), by taking a curve in either directon or both, at speed or by turning the steering wheel while the noise is present as you would if you changed lanes to pass a vehicle ?

What happens when you let off the gas ?
What happens if you let off the gas and depress the clutch pedal ?
Will anything alter the sound other than slowing down ?


Hi there. it is a lower pitched sound (a muffled whining so to speak). Zzzinging is a good description. Not a growling or grinding sound.

The sound only changes when I accelerate - regardless of whether I am going around a curve or going straight or turning the steering wheel.

When I let off the gas the sound decreases as the car slows down. I haven’t paid attention to the sound when I depress the clutch pedal. I have only noticed the sound diminishing when the car slows down. Nothing alters the sound other than slowing down.

I did go to the dealership and they say it is most likely the front differential. They lifted the car onto the hoist and spun the wheels to check for possible wheel bearing but heard nothing. Good news is that I had the front differential replaced 6 months ago so it is under warranty. Know I want to know why so soon?

Kay, Thanks For The Information. We Appreciate Feedback.

There are many Subaru owners who monitor this site. Maybe they can offer some opinions to your question, "Good news is that I had the front differential replaced 6 months ago so it is under warranty. Know I want to know why so soon? "

Good Luck,