BMW howling sound from the rear end.

arny14 · Post by **arny14** » Thu Jul 13, 2023 10:41 am

Hello,

[E85_200_3.0_6_speed_manual]

I have this weird noise https://www.youtube.com/watch?v=_GPyuxuyJRw around 20-30km/h (12-18mph) during the acceleration. Now I changed the differential, but the issue is still the same.

I have poli bushings, but the noise was noticeable with the originals too.
Maybe every diff has this sound? Or coming from the different area? Any idea?

brillomaster · Post by **brillomaster** » Thu Jul 13, 2023 10:51 am

first thought for rotational noises is usually a wheel bearing...

arny14 · Post by **arny14** » Thu Jul 13, 2023 10:59 am

Yes, that occurred to me too, but none of the YouTube videos have such a noise, they were more like growls.

MikeyH · Post by **MikeyH** » Thu Jul 13, 2023 2:27 pm

Something to do with the prop shaft ? Universal joint, is there a clunking noise when you lift of the accelerator?

enuff_zed · Post by **enuff_zed** » Thu Jul 13, 2023 2:57 pm

If it's at just those speeds is it resonance? Something vibrating at just that frequency?

firebobby · Post by **firebobby** » Thu Jul 13, 2023 3:03 pm

I had a wah wah wah wah noise from the rear, turned out to be the rear tyre's had gone out of shape.
Nice and quiet now

arny14 · Post by **arny14** » Thu Jul 13, 2023 5:14 pm

Hey, no clunking noise, but the howling only come during the acceleration, also changed the tires 2 weaks ago. Yes maybe resonation, but i cannot find any loosen suffs, and i think it should resonate both during accel-deccel.

MikeyH · Post by **MikeyH** » Thu Jul 13, 2023 6:27 pm

Do you have split rims, are the screws tight? Someone else on here had an odd noise and the screws were loose.

Pondrew · Post by **Pondrew** » Thu Jul 13, 2023 7:37 pm

MikeyH wrote: ↑Thu Jul 13, 2023 6:27 pm Someone else on here had an odd noise and the screws were loose.

There are a few on here with a screw loose, mate!

MikeyH · Post by **MikeyH** » Thu Jul 13, 2023 8:19 pm

Pondrew wrote: ↑Thu Jul 13, 2023 7:37 pm
MikeyH wrote: ↑Thu Jul 13, 2023 6:27 pm Someone else on here had an odd noise and the screws were loose.
There are a few on here with a screw loose, mate!

I thought they had been banned

oopps

ml1nov1980 · Post by **ml1nov1980** » Wed Jul 19, 2023 9:05 pm

2011 z4 30I
I'm getting a slight humming sound from the rear differential area. changes intensity with the rpm change? I've changed the fluid but noise still there? 105k miles any one have any ideas?

firebobby · Post by **firebobby** » Wed Jul 19, 2023 9:58 pm

ml1nov1980 wrote: ↑Wed Jul 19, 2023 9:05 pm 2011 z4 30I
I'm getting a slight humming sound from the rear differential area. changes intensity with the rpm change? I've changed the fluid but noise still there? 105k miles any one have any ideas?

Check your rear tyre's, mine had gone out of shape, I thought my diff was going. New tyre's and nice and quiet now.

GreyZed · Post by **GreyZed** » Wed Jul 19, 2023 10:53 pm

Don't under estimate how much noise tyres can make. I had a set of cheap tyres on an E85 I bought and I stopped 3 times on the way home that day they made so much noise - thought a wheel bearing was disintegrating! Put new tyres on a week later and silence.

ml1nov1980 · Post by **ml1nov1980** » Thu Jul 20, 2023 2:22 am

firebobby, from ml1nov1980. When you were getting noise from your tires did the noise go up and down with the rpm's?? The noise I have will increase slightly in sound when I accelerate and then stop when I let off the gas?? So It must only make the sound when it is under load or torque? I'm thinking tires would be a constant hum sound and not change with the rpm?? Your thoughts!! I do have the run flat tires on the car, very noisy, and rough riding but still in good shape! Thanks for the response! Mike

firebobby · Post by **firebobby** » Thu Jul 20, 2023 5:40 am

ml1nov1980 wrote: ↑Thu Jul 20, 2023 2:22 am firebobby, from ml1nov1980. When you were getting noise from your tires did the noise go up and down with the rpm's?? The noise I have will increase slightly in sound when I accelerate and then stop when I let off the gas?? So It must only make the sound when it is under load or torque? I'm thinking tires would be a constant hum sound and not change with the rpm?? Your thoughts!! I do have the run flat tires on the car, very noisy, and rough riding but still in good shape! Thanks for the response! Mike

I'm not sure, but think it did. I found run flats, terrible for handling on my car.
How old are they, try jacking the rear up and running it in gear, see if the tyre's are out of shape.
Like I said, my tyre's were the cause of the noise, and it sounded like the diff/bearing noise.
Hope that helps

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