Wooing sound around 35-40mph

[Gill]

Hi,

I’ve got 2004 Subaru Forester XT 2.5 with 5-gear manual transmission.
Car has around 80k miles on it.

The problem.
Wooing sound when driving around 35-40 mph.
Only when accelerating, best noticeable just after I put my foot on the throttle.
It happens on all gears (for sure on 2nd,3rd,4th), sound is little different in pitch on each gear tough.
It was the same on winter tires as it is now on summer tires
When I’m decelerating there is no wooing sound.
I’ve put car on jack stands, accelerated around this speed and there was no wooing. I was trying to hear something around the wheels, transmission and rear diff, but everything sounded ok. Maybe a little louder near transmission, but characteristic of the sound was different.

This is frustrating because it happens on speed that I usually drive around the city.

Thanks in advance for any help,
g.

Topic

[dave]

being that the sound occurs during acceleration only, I would suspect the differential ring and pinion.

[exceptionalchris]

Noises can sometimes be hard to find. I would inspect serpentine belt, tensor, or bearings. It is also possible an alternator bearing could be going out. Note, careful with the tensor on this vehicle because of the design it is easy to brake. Look up the repair manual for assistance. Hear are some videos to help.

[Jameson]

wooing? could you describe it as growling or howling? usually the sounds that occur during acceleration at a certain speed, and in the wheel area, are failed wheel bearings. you can swap tires to rule out a tire issue. with the vehicle lifted (jackstands or whatever), spin the wheel and hold on to the coil spring, you can usually feel a bad wheel bearing. it will feel like a rough, crackly feel, where as a good wheel bearing, you wont feel much of anything.

[Bill]

Sounds to me like there is a bad bearing in the transmission somewhere. Probably the input shaft bearing. Check the fluid for the correct level.

I would have a professional drive it for their opinion to prevent other possible damage.

[Walter Cheryba]

Check all your engine and transmission mounts. I suspect this since your jackstand test did not produce the noise. Things load and flex differently with the vehicle on the road. Worth a look.

[Gill]

Thank you all for answers.

Sound is more like howling.

When car was on jack stands I rotated all wheel and didn’t feel anything more than disc rotor rubbing.
Only thing I noticed was that rear wheels were around two times more difficult to rotate than front, but I thought it was because of rear diff

I have little cracks on serpentine belt and was planning to change it next week, so i will know if it’s it soon.

There is new Motul oil in transmission and the level is correct.

I will try to check the mounts of engine and transmission later this week.

Please let me know what do you think about rear wheel more difficult to rotate than front – is it normal?

[sam priem]

the rear wheel is going to be harder to spin. Thats normal, your trying to turn more than just the wheel in the back whereas the front youre only spinning the wheel.

I agree to have a pro take it for a drive and get thier opinion. I would lean more towards a trans bearing (either input or output) or the rear differential.

[Author]

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