Quiet whining noise
 

Not having much luck with the D3.

I had the exhaust leaks fixed last week, so now the car is silent when driving along, but now have a couple of sounds which were obscured by the loud exhaust.

Once the car warms up when driving at 70mph there is a noticeable whine coming from somewhere, This whine is stops if pull into the services on the motorway for say 1/2 hour, but will return a short while later.

Also when coming to stop with a small amount of steering input there appears to be a slight judder just as the car comes to a stop. There is no problem when travelling in a straight line.

Now I have alarm bells ringing, thinking Diff or Transfer box problems. If I shift to N on the motorway the sound remains but seems to get quieter. At 60mph you dont really here it, and at 80mph its not noticeable either.

All four tyres currently have different tread levels, so once the D2 is sold they will all be replaced. Not sure if this is the cause but there will be rotational speed differences across all four corners.

This weekend the car has been driven quiet a few miles,

Blandford to Cambridge, then Cambridge to Bury St. Edmunds via Elveden, Then Bury St. Edmunds back to Cambridge, Cambridge to Stevenage, Stevenage to Blandford.

Listening as much as I can, I have not worked out where the sound is coming from apart from it appears to be from behind me, I cannot be 100% sure though.

Observations.

At 60mph the sound is still there, but the frequency is lower than 70mph.
At 75mph the sound is still present but higher frequency.
The sound varies with road speed, and not engine RPM. Shifting down manually the sound does not change.
Lifting off the throttle, the sound returns after a short period even whilst slowing down.
If when driving you ease of so the car is neither slowing down or speeding up the sound goes much quieter.
If you floor it the sound goes away until a steady speed is obtained.

First port of call is going to be replace tyres I think, then the diff oil perhaps if the tyres don't fix it. I dont think its a wheel bearing, although again cannot be 100%. Even after driving 100 miles, I checked the wheel temperatures at Winchester services and all 4 wheels where stone cold so its not brakes either.

You may as well change the diff oil. The rear is easy and the front is a little harder as it requires an oil extractor as there is no drain.
I used FUCHS Fuchs Titan Sintopoid 75W-90 Axle/Diff Fluid from Opie Oils as it meets the VAG spec. ELSAWIN workshop manuals are available from ebay, TPB etc...

This juddering sound is starting to bug me somewhat. Did it twice today pulling up at lights, its not the brakes.

You don't feel anything through the pedal, or feel anything coming through the steering, its audible only. Does it even under the lightest of braking and always just as the car is about to stop. its very quiet and would have easily been drowned out by the exhaust being holed. Both events today were in a straight line.

I am beginning to think something that's not nice is going on with the drivetrain.

More diagnosis, this is quiet worrying and not sure what to make of it. I'm picking up the buyer of my D2 from Salisbury on Sunday, so another pair of ears will be able to witness the fault.

The judder/shudder or whatever you want to call it happens as I say when stopping, but it does it in both 'D' and also when coasting to a stop in 'N'. You do not have to be on the brakes either, it will sometimes do it just coasting to a stop in 'N' with no feet on any pedals. The speed concerned is less than 1mph, you could walk faster than the speed where the sound occurs. If I brake hard to a stop, nothing the car pulls up fine everytime.

Thought maybe its a dodgy engine mount, so this evening I opened the bonnet put the car in D and foot on the brake, then pressed the accelerator, the engine hardly moves. Tried reverse with foot brake, same result so its not the mounts.

Then there is the quiet whine when at speed, no sound at all in town.

Scanned the car for fault codes as well, Engine - nothing, Auto Trans - nothing.

Weird, very weird.

If it does it in N then unlikely to be the box... maybe a gearbox mount or suspension bushes.

the bmw and jag versions of the box are known for thumping into 1st when stopping (the wifes x5 does it).

Sounds like suspension bushes to me, somewhere on front arms

The tyres are being replaced on Monday, all four.

I cleaned the car today, found the nearside rear tyre almost bald in the centre of the tread so obviously been overinflated at some point. Confirmed by the local tyre place, who did not have any tyres in 255/40x19 (sleepy Dorset for you).

I popped to the local garage to check the pressures, FR - 35PSI, FL - 35PSI, RR - 35PSI, and I was expecting a high reading on the otherside, but no RL was running at 20PSI so it was 15PSI down.

Tyres are all now 35PSI, the judder/shudder is still there, I'll report again once the new tyres are on.

I cannot imagine why new tyres would fix the shuddering

Confirmed, it hasn't.

Four new tyres now fitted, and the best of the old ones transferred to the spare as it was an odd size. Will report if the whine is any different when I get to drive at 70mph again, not very often in Dorset as hardly any dual carriageways.

This evening will be the moment of truth, driving 150 miles and will be on the A31, M27, M3, M25 and A1, plenty of opportunity to see if the whine has gone.

I know the shudder sound is still present, it still does it almost daily at some point. Still not got to the bottom of that, could be bush related or perhaps transmission or engine mount related.

After driving 150 miles last night, I can confirm the whine is still present but seems quieter.

The shudder is still present as well, this seems to always sound the same.

I also drove 80 miles yesterday with passengers, so we all had a good listen. Whine is definitely in the rear, but its location is inconclusive.

The whine is quiet loud on deceleration, for example lift off at 70mph and you can hear it, and the frequency drops as the car slows down. Apply throttle and the sound gets quieter, speed up and the sound goes all together.

The whine will stop completely if you move from Drive to Neutral thus disengaging the transmission. Revving the engine and the noise does not return, put the car back in drive and the sound returns.

When we arrived at our destination yesterday, we had a feel of the temperature of all road wheels. Not sure but its possible that one wheel was warmer than the other at the back of the car.

Still suspecting rear diff or wheel bearing at this stage.

Your whine is different to mine. Mine is purely engine RPM so would return in N when revving. Yours sounds more like rear diff, so maybe you could change the fluid. It's very easy to do, easier than changing engine oil. Mine was jet black like cocacola when it was replaced.

You can use infrared thermometer to check tyre temperatures. I have done it to dial in TOE without going for wheel alignment.

I also posted this on audiworld to get a view from the other side of the pond.

Audi have a TSB for what this sounds like
http://ebookbrowsee.net/tsb-audi-a6-...pdf-d232161926

I wonder if this is my issue, and what could I do to get Audi to check, assuming the same TSB applies to the UK as well as USA.

Have a look to see if it is black as in the TSB, I looked and mine is silver, PR code FNL (tdi not listed on the US TSB.
My car was built ~ December 2005 and registered Feb 2006.
Good luck, I would try new oil before a diff swap though.

I've found a reasonably local diff and transmission specialist, I've buzzed them an email but not had a reply yet. If I dont here soon then I'll give them a call and see if they can help diagnose the rear end noise.
http://www.wimbornemotors.co.uk/axle...erentials.html

Well my car is still whining but I think I have found the source and its not diff. Managed to get a chance to sit in the back with someone else driving, tracked the source of the noise to the NS wheel bearing. The noise has got no worse or better since starting this thread so will need to keep an eye on it.

I too get a whining in the car on long journeys, it usually starts after about 30mins of driving and will require stopping somewhere convenient for a short break.

Its usually not long after setting off again before it returns.

I don't think I will ever be able to cure the problem, been with her for 11 years now so cant see her changing her ways in the foreseeable.

Good news on finding the source of yours though +++

I have a whine on mine also.

Thought I would mention it so I could join the club +++

Mine is when I lift off the throttle and the car slows a little from 70 to 65 mph.

No other time do I get it, never got any worse but I suspect gearbox and possibly a bearing.

:ROFL::ROFL::ROFL::ROFL:
Mine does exactly same thing, but it gets worst during the sharp turns or going to fast on the roundabouts +++

I spent a while listening to the car off throttle from 70 to 65 today and I have convinced myself its more to the rear of the car.

So maybe gearbox, maybe diff or a wheel bearing.

Though that's the next task after I have got the heating working!

Has anyone checked their power steering reservoir? Its totally hidden in the V10's and is likely overlooked during servicing.
I had a whine and noticed the engine sounding loaded when turning the wheels while parked. Turns out the fluid was well down. Top up fixed it. Since then I do the whining, and every time it's in for anything I insist that check/top up the PAS

My Lwb also dose this at 70mph when you lift the throttle and slow down to 60 or so.
im going to change the diff oil and see if that cures it. gearbox has been serviced and its still doing it. maybe just a D3 thing ..it is only very faint

PAS fluid.... just saying
And what about fuel pumps?