A8 Parts Forum  

Go Back   A8 Parts Forum > A8 D4 > D4 - Axles, Brakes, Suspension and Steering

D4 - Axles, Brakes, Suspension and Steering Brakes, Springs, shocks, steering racks, steering columns, suspension arms, wheel hubs etc.

Reply
 
Thread Tools Display Modes
  #1  
Old 24th February 2016, 07:42 PM
velour velour is offline
Junior Member
 
Join Date: Jun 2013
Posts: 11
Default Droning noise from D4 4.2tdi

Hi all,

Have a D4 4.2tdi that I bought 2 1/2 years ago with 27k. It's now got 57k miles.

Yesterday it started making a noticeable droning / humming noise, difficult to tell where it comes from but gets worse with road speed. It's worst at about 70 going down to 50 with engine braking.

On a trip to Southampton today the sports differential warning light (yellow) came on but has now gone again. Took it to a dealer who cleared the warning, took it for a test drive and said they could not find anything wrong. Noise is still there though. Definitely not tyres as new ones fitted very recently.

Any thoughts on how to proceed - just brace myself and go back to the dealer to investigate the noise? Is it likely to be anything other than the diff?

Cheers
Reply With Quote
  #2  
Old 24th February 2016, 08:03 PM
Delboy's Avatar
Delboy Delboy is offline
Senior Member
 
Join Date: Aug 2013
Location: Lowestoft, Suffolk
Posts: 2,492
Default

If you have a noise like that along with a warning about the diff I would looking at that further, even if you have to get creative and secure a go pro wrapped in foam and tied onto the diff just to see if you can get a recording from it.

Is the car still in warranty? if it is i would push the issues before it expires.
__________________
Del

Reply With Quote
  #3  
Old 24th February 2016, 08:11 PM
paulrstaylor paulrstaylor is offline
Senior Member
 
Join Date: Jul 2010
Location: Manchester
Posts: 1,317
Default

Had a drone on my D3, same drive train, was a rear wheel bearing.

Never any warning lights though, I'd doubt the diff warning light was a coincidence!?
Reply With Quote
  #4  
Old 24th February 2016, 08:47 PM
Architex_mA8tey's Avatar
Architex_mA8tey Architex_mA8tey is offline
Moderator
 
Join Date: Jan 2009
Location: London/Oxford/Swindon
Posts: 7,648
Default

Quote:
Originally Posted by paulrstaylor View Post
Had a drone on my D3, same drive train, was a rear wheel bearing.

Never any warning lights though, I'd doubt the diff warning light was a coincidence!?
Yep id agree - had a rear wheel bearing go on a D3 which gave a similar droning noise, it just got louder gradually until we changed it.
__________________

Confidence is the feeling you have before you know better . . . .
Audi A8 D2 3.7 Quattro Sport 1999 FL - Melange
2nd Place Winner - A8-Freunde Annual German Meet 2012 at Edersee
20" x 9" Bentley GTC Wheels with 385mm W12 Front Discs & Bentley Caliper Covers, Front Lowered on Coilovers, Xenons, Combined DRLs and LED Foglights to modified OEM front fog lamp position, Alcantara/Leather, Full Black Alcantara headlining + pillars and blind shelf, Bespoke Flat Bottomed Sports Steering Wheel, Dark Myrtle Wood, Autodim Mirrors, Bose, Blinds, Digital TV, Ski Hatch, Modified rear exhaust section for extra V8 Burble
Audi S8 D2 Final Edition 2002, Avus Silver with Red Leather Interior
Tiptronic with Sport mode button, Sony rear entertainment package, Bose sound system, Audi Navigation Plus, 20 inch Final Edition alloys, Full Cat Back Stainless Milltek exhaust, giving a great V8 burble
Audi A8L D2 4.2 Petrol with LPG - Ebony Black
Audi A8L D4 FL 4.0T Petrol twin turbo - Havana Black
Audi A2 1.6 FSi Sport - Dolphin Grey with Votex body kit and Red Leather Interior
and some other A8's A8L's and Mercs
Reply With Quote
  #5  
Old 24th February 2016, 08:48 PM
Pug Pug is offline
Member
 
Join Date: Oct 2015
Posts: 95
Default

You say you had new tyres? Front or rear or all 4?
Reply With Quote
  #6  
Old 24th February 2016, 09:00 PM
Joe2.0E Joe2.0E is offline
Senior Member
 
Join Date: Feb 2012
Location: Ireland
Posts: 428
Default

I also think the diff is most likely given the noise has just started suddenly. A wheel bearing wil gradually get nosier unless the bearings suddenly collapse.
I have similar miles on a D4 3.0TDI without any issues but i dont have the sports diff. My previous D3 had one rear wheel bearing replaced after a similar droning noise but it was at about 150k miles.
If you are out of warranty, it would be worth having the diff oil changed, condition of the old oil might indicate if the diff is in trouble. Shouldnt cost much to have it done.
Reply With Quote
  #7  
Old 24th February 2016, 09:02 PM
Lee S Lee S is offline
Senior Member
 
Join Date: Jul 2013
Location: South Wales
Posts: 512
Default

Quote:
Originally Posted by velour View Post
Took it to a dealer who cleared the warning, took it for a test drive and said they could not find anything wrong.
Take that with a very large pinch of salt. I had an alleged Audi "Master Tech" tell me that he "had no idea what was wrong with my EPB" and to "exercise it a few times and give it a couple of days to settle back down" when all it needed was the basic "place in park and turn ignition off with handbrake off" calibration and it was fixed.

If the diff light came on and it was making that much noise, get it to someone who will give you a better diagnosis other than "dunno mate.. seems alright to me"...
__________________
Lee
2017 Nissan Leaf Tekna
Reply With Quote
  #8  
Old 24th February 2016, 10:03 PM
paulrstaylor paulrstaylor is offline
Senior Member
 
Join Date: Jul 2010
Location: Manchester
Posts: 1,317
Default

Quote:
Originally Posted by Joe2.0E View Post
I also think the diff is most likely given the noise has just started suddenly. A wheel bearing wil gradually get nosier unless the bearings suddenly collapse.
I have similar miles on a D4 3.0TDI without any issues but i dont have the sports diff. My previous D3 had one rear wheel bearing replaced after a similar droning noise but it was at about 150k miles.
If you are out of warranty, it would be worth having the diff oil changed, condition of the old oil might indicate if the diff is in trouble. Shouldnt cost much to have it done.
The bearing on my D3 started groaning clear as day one day, parked it up after a 200 mile drive, no noise - came back a few hours later to drive home, groaned all the way home. Was like that for a few 1000 miles until I isolated which bearing and got it booked in, my initial worry was the diff!

That said, oil change won't hurt and may as you say tell a story!
Reply With Quote
  #9  
Old 25th February 2016, 08:18 AM
velour velour is offline
Junior Member
 
Join Date: Jun 2013
Posts: 11
Default

Hi all,

Great answers - thanks very much. Sounds like the way forward is to ask for some help in changing the diff oil and in isolating whether there is a wheel bearing issue. Trip to the local indy will be booked today.
It is out of warranty (by 6 months grrrrr) and had all 4 tyres changed and tracking done. The noise was evident before and after the tyre change.

Does anyone happen to know what would trigger the sports diff system warning? No idea what sensors feed into it - maybe the abs sensors?

Cheers

Last edited by velour; 25th February 2016 at 08:21 AM.
Reply With Quote
  #10  
Old 25th February 2016, 08:34 AM
paulrstaylor paulrstaylor is offline
Senior Member
 
Join Date: Jul 2010
Location: Manchester
Posts: 1,317
Default

I'd say the first step would be to get a mechanic in the back of you car to listen to the noise, just spinning the wheel on mine on the ramp didn't trigger any noise, had to be under load and at motorway speeds.

Ended up with a tech crawling all over the back seat on the M60 for him to work out which side it was, apparently the sound deadening doesn't help. He said that the main dealers use a microphone setup clipped to various points on the suspension to isolate, his method proved to work also
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT. The time now is 06:04 PM.


Powered by vBulletin® Version 3.8.0
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.