Humming Noise coming from drive line!!

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Humming Noise coming from drive line!!

Postby LORD-GRAVEL » Sat Oct 24, 2020 7:48 pm

Hello all,
I have a 2007 Subaru Liberty 2.5 Automatic, have loved the car but a few weeks ago a humming noise started.

The noise only appears when about 60km and gets louder as you speed up.
Completely Speed related - does not change with the engine revs.
I have put the car up onto stands and the noise seems to be coming from the gearbox region.

it is not any of the wheel bears as I have replaced all of them.

in short, I am at the point of just getting another gearbox to see if it will stop the noise.

has anyone had any experiences with this?
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Re: Humming Noise coming from drive line!!

Postby bigBADbenny » Sun Oct 25, 2020 5:59 am

How old are the tyres?
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Re: Humming Noise coming from drive line!!

Postby bigBADbenny » Sun Oct 25, 2020 6:49 am

Try a site specific google search, you’re unlikely to be the first with this issue:

https://www.google.com.au/search?sxsrf= ... =278&dpr=2

Here’s an example search with a couple of promising hits, feel free to refine the search keywords to see more results.

For an even larger user base, repeat the search on Eg LGT and other forums, here’s another example:

https://www.google.com.au/search?client ... s-wiz-serp


....
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Re: Humming Noise coming from drive line!!

Postby LORD-GRAVEL » Sun Oct 25, 2020 7:31 am

bigBADbenny wrote:How old are the tyres?
the tyres are fairly new (less than 10k on them) it didn't make the noise before a few weeks ago.

bigBADbenny wrote:Try a site specific google search, you’re unlikely to be the first with this issue:

https://www.google.com.au/search?sxsrf= ... =278&dpr=2

Here’s an example search with a couple of promising hits, feel free to refine the search keywords to see more results.

For an even larger user base, repeat the search on Eg LGT and other forums, here’s another example:

https://www.google.com.au/search?client ... s-wiz-serp


....

I have looked on most of the Subaru forums, but every case of a similar sound is always on an MT box, not an auto box. a mate told me to check the tail shaft for any movement in the centre bearing. so I will be doing that today.
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Re: Humming Noise coming from drive line!!

Postby bigBADbenny » Sun Oct 25, 2020 9:02 am

Very good.
Would you like me to check the results in the searches for you?
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Re: Humming Noise coming from drive line!!

Postby jdmsubielover » Fri Dec 04, 2020 3:42 pm

Could be a wheel bearing if the noise changes with speed of the vehicle.
07 Gen 4-BL 2.5i -5 spd man
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Re: Humming Noise coming from drive line!!

Postby bigBADbenny » Sat Dec 05, 2020 9:12 am

I did google it and centre diff was one possible...
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Re: Humming Noise coming from drive line!!

Postby RX25SE » Sat Dec 05, 2020 5:45 pm

No center diff on auto trans IIRC.

Bearings usually rumble and tyres humm. Have you got another set of rims you could throw on it?

If it's not the tyres then I'd start with the tail-shaft support bearing seeing as you said the noise was there on stands. A big arse screwdriver held against the bearing mount with the handle against your ear is a good way to listen for noisy bearings. Works well on engine pulley bearings.

Wheel bearings won't be loaded on stands, but on the road if you swerve gently left and right a wheel bearing will change note slightly as the side loading changes with the swerve. Can be a bit hard to pick though.
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Re: Humming Noise coming from drive line!!

Postby bigBADbenny » Wed Dec 09, 2020 4:52 pm

You’re absolutely correct, but they do have something or other transferring power front and rear and it can get issues:
https://www.subaruforester.org/threads/ ... eat.86888/

They also buzz apparently:
https://www.google.com.au/search?q=suba ... ent=safari
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