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Unusual noise from rear on deceleration

Posted: Wed Dec 09, 2015 9:44 pm
by RS4GCI
Hi, I'm hoping you knowledgable folks can help. I have a niggle with my RS4 that I'm keen to find out if anyone has experienced the same.

Basically my RS4 in every respect drives perfectly, has covered 46k miles and is a pleasure to drive. However I have noticed on deceleration and in gear there is a whine coming from the rear only between 40-45mph and this only occurs when decelerating. It is more audible in gear. When I dip the clutch at that speed and on deceleration it becomes less audible.

It's definitely coming from the rear and weirdly when I push the car harder it's less noticeable. It's more noticeable when cruising but always on deceleration.

I'm thinking rear diff but I've trawled the net and can find little evidence that this generation of RS4 suffers from any differential issues. I've seen some folk talk about diff issues with the B5 but struggling to find anything on the B7.

It doesn't sound like wheel bearing and I would have though that would be at all speeds. Car has same tyres all round and in good condition.

I haven't approached any garages yet but I'd appreciate it if anyone has experienced this or knows of anyone who has.

Thanks

Re: Unusual noise from rear on deceleration

Posted: Thu Dec 10, 2015 8:20 am
by coffey555
My one does that as well, faint brrrrrrrrrr noise as you lift off the throttle. It makes quiet noises at other times as well and has done so since I got it. I think it is just a trait of the quattro drivetrain.

Has the rear diff oil ever been changed?

Re: Unusual noise from rear on deceleration

Posted: Thu Dec 10, 2015 10:06 am
by TomRS
Get to a local TPS dealer and change the rear diff oil its simple to do yourself you'll need a gearbox syringe.

See if that makes a difference then go from there, even though miles are low oils been in for some years now, it might have just broke down and need replacing, the whine is usually worn gears inside the diff, pininon bearing.

Re: Unusual noise from rear on deceleration

Posted: Thu Dec 10, 2015 10:29 am
by RS4GCI
Thanks for the comments. Oil change was next on my list to do, both gearbox and diff. I'll see if that makes any difference.

I thought the Quattro drive train was pretty tough, I'd be amazed and disappointed if the diff gears have worn in 46k miles. I could understand if it has been run dry of oil but I would have thought that would be pretty rare??!

The only other thing I picked up from researching the net was diff bearings or propshaft bearings. I'm not entirely sure how you diagnose that though.

Re: Unusual noise from rear on deceleration

Posted: Thu Dec 10, 2015 8:19 pm
by R1RS4
If things go horribly wrong there's a diff on Fleabay currently at 99p

Item number 131672713665 love The postage cost

Re: Unusual noise from rear on deceleration

Posted: Thu Dec 10, 2015 8:35 pm
by Harris.
R1RS4 wrote:If things go horribly wrong there's a diff on Fleabay currently at 99p

Item number 131672713665 love The postage cost

Im the guy selling the diff on Ebay , postage costs are cheap as I run a courier company .it needs a clean on the outside as its been off the car for over a year .

Also just to note changing the oil in the diff will make no difference at all , if its worn new oil wont fix it . Normally when coming off throttle the gears are obviously slowing down . it will be a diff rebuild or new diff . Also check the drive shafts

I have them also . in the for sale section .

Re: Unusual noise from rear on deceleration

Posted: Thu Dec 10, 2015 10:52 pm
by R1RS4
Harris. wrote:
R1RS4 wrote:If things go horribly wrong there's a diff on Fleabay currently at 99p

Item number 131672713665 love The postage cost

Im the guy selling the diff on Ebay , postage costs are cheap as I run a courier company .it needs a clean on the outside as its been off the car for over a year .

Also just to note changing the oil in the diff will make no difference at all , if its worn new oil wont fix it . Normally when coming off throttle the gears are obviously slowing down . it will be a diff rebuild or new diff . Also check the drive shafts

I have them also . in the for sale section .
Some good advice there, good luck with your sale

Brilliant to see a Fleabayer that's real fair on shipping costs

:biggrin3: :blackrs4:

Re: Unusual noise from rear on deceleration

Posted: Sun Dec 13, 2015 11:31 pm
by taylora
hi
dont discount a stone or something trapped in the brakes somehow or other.

a while back i had an odd sort of whine, only really noticeable on the overrun. and occasionally a soft soft of clunk clunk related directly to wheel speed coming from the rear.
took it to the local garage in the village who are really good at the basics on just about everything to get a first opinion before sending it to audi. they recommended taking the brakes apart first, rather than start replacing things which inevitably is the result somewhere more expensive.
So a couple of hours of their time to take the calipers off, give them a good clean out and then back on, at the same time check the cv joints as well. when it went back together there was no noise and has not been since.

a very lucky result really. they thought that perhaps all the standing water that had been around had pushed some stones into somewhere they shouldn't of been, you might get lucky as well and have a similar cause ?

Re: Unusual noise from rear on deceleration

Posted: Mon Dec 14, 2015 10:31 am
by RS4GCI
i'll certainly be giving the rear brakes and bearings a check over to eliminate them. there is no clunking or any other noise apart from a whine between 40-45mph on deceleration, either side of that speed there is no noise. I'll have to get it checked out and see if I can get it diagnosed.

Re: Unusual noise from rear on deceleration

Posted: Mon Jan 21, 2019 7:45 am
by dillonc
Sorry for bringing back the old thread.

I’m having similar whining sound recently, after putting stiffer rear differential mount on...
It only occurs between 55mph-35mph when I let off gas coasting or braking within that speed range.

If I disengage from gear, the sound disappears...
Is it really the differential needed re-build?

Any thoughts? Thanks!