Wheel bearings or something else?
 

Hello folks

Wasn't sure whether to put this in the Suspension or Tranmission section

My recently acquired S8 has always had a rumble audible at speed (40-50 mph plus), which I was hoping would be because of the worn and mismatched tyres all round.

Well, tyres replaced all round today with new Goodyear Asymetric 2, however the 'rumble' is still there and gets louder at speed, irrespective of whether i'm cornering or in a straight line. It quickens with speed, so at 70mph its almost like a washing machine on spin cycle.

Sounds like failed wheel bearings, but as the noise doesn't change with directional changes, i'm less convinced.

What else could cause a similar type of rumble? Quiet at 30mph or so, but gradually gets louder with speed. No vibrations or anything else.

Gearbox was refurbed <10k ago by RA Engineering in Reading, so really hoping its not this! Upshifts appear fine to me, minor stumble when coming to a stop on downshifts. Gearbox drain and refill just completed, but no change on the rumble.

Could it be bearings? low diff oil? driveshafts?

Thanks in advance

So not wheel bearings but a failed LhS driveshaft!

£500 ish from Audi!

Ouch, you not consider a second hand one from A8 parts, they must have loads.

Unsure about used driveshafts, could be a false economy ?

Just hope it cures the rumble - I had my hopes it was the ropey tyres :rolleyes:

So a grand spent trying to solves this!

Was driveshaft bent? There is nothing else to go wrong on the shaft itself and second hand would be fine. Or was it CV joint on driveshaft? They can be replaced on their own and can be bought cheaply. When I got my D2 CV joint boot was split and it looked like it has been like that for a while with dust and water getting in so I decided to replace joint as well not just the boot, It was about £20 for new aftermarket unit. But some are odd sizes or spline count and hard to get without cheap alternatives but still cheaper then the whole driveshaft.

I'm told there was movement at both cv joint end and the hub end, if I've got that right?

Was deemed a false economy to just replace cv joint alone

Worse still Audi have sent the wrong part so another 5 day wait till it arrives / grrrr

Is the driveshaft not like the normal ones where each end has a joint fitted, I have never heard of a drive shaft being required during the life of a car unless it was in an accident or it was snapped due to mental power or bad design.

Normally one would replace the joints either end???

Yes they are.Here are the links for both joints from the same company I bought outer CV joint 6-7 years ago and still going strong also I don't do much mileage. Looks like it is even cheaper than when I bought it.
Inner http://www.ebay.co.uk/itm/AUDI-A8-QU...item20bd3bb7c9
Outer http://www.ebay.co.uk/itm/AUDI-A8-In...item1e58655b6a

Thanks chaps - Really useful

Will contact the garage to see what they say. They could have them by Tuesday

Ok, just contacted the garage - they're happy to give these a go but have raised a concern that the splines on the shaft itself maybe at fault and the joints may not solve the issue.

£30 odd was cheaper than £500 last time I checked so will order these in.

Thanks again chaps :)