Droning noise from D4 4.2tdi

[paulrstaylor]

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!?

[Architex_mA8tey]

Originally Posted by paulrstaylor

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.

[Pug]

You say you had new tyres? Front or rear or all 4?

[Joe2.0E]

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.

[paulrstaylor]

Originally Posted by Joe2.0E

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!

[velour]

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

[paulrstaylor]

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

[Mechcanico Lee]

The noise you describe sounds like a bearing but I can't see why it would bring a diff light on , does the d4 have some kind of active diff with limited slip control .
If you turn on a tight lock does it have any sort of binding feel to it

[ainarssems]

I think it has hydraulic controlled sports diff, they do suffer from high pressure sensor faults, electric and software problems on different Audi models.

Considering you have droning noise it could be wheel bearing worn letting the hub to move around a bit and affecting ABS sensor readings and that confuses diff control. But I would expect it to bring up ESP and/or ABS lights as well. Check the wheel bearings, log ABS sensor readings while driving and check the fault codes.

[Dezzy]

Glad it's sorted.

But one thing worth remembering here the "master tech" confirmed it is the electronics making the light come on but also couldn't find anything wrong with it to start with. I'm not an electrician or a "master" tech even i know it electrics that make a light work.