Hum, thrum, thrum sound almost certainly not wheelbearing

[996TurboUK]

I am hearing a noise that I can best describe as wheel-bearingey like thrum, thrum, thrum, similar to the sound you get when one sector of the bearing is damaged, but the main difference being the frequency of the thrumming is much higher than wheel rotation (but is still related to vehicle speed).

It sounds like the thrum, thrum is around 3 times wheel rotation speed. Best heard at low speeds, say 10mph, and in gear or out makes little difference (heard best coasting). At higher speeds due to the frequency increase it just turns into a whine.

Any ideas?

[JuncoJones]

I am hearing a noise that I can best describe as wheel-bearingey like thrum, thrum, thrum, similar to the sound you get when one sector of the bearing is damaged, but the main difference being the frequency of the thrumming is much higher than wheel rotation (but is still related to vehicle speed).

It sounds like the thrum, thrum is around 3 times wheel rotation speed. Best heard at low speeds, say 10mph, and in gear or out makes little difference (heard best coasting). At higher speeds due to the frequency increase it just turns into a whine.

Any ideas?

 

If you can post a recording of the noise that will certainly help with the diagnosis..otherwise it's kind of shooting in the dark..

 

One time I got some sort of metal shavings inside the drilled disc holes, but that was easier to pinpoint as it was one noise per wheel rotation, not three.

 

Cheers

[Hilux2400]

Does in increase with the outer wheels when cornering?  

[wizard]

How many 'spokes' on your wheel?

[996TurboUK]

Off another forum I got very strong pointers towards a gearbox pinion bearing.

 

As an aside - re the wheelbearings - even when shot, the sort of bearing fitted tends not to make any increase in rumbling sound under cornering loads. Replaced my fronts and the only 100% confirmation they were shot (other than the noise) was had when they were in my hands and opened up.