New old Car yesterday = today loadsa faults

[NICNAC180579]

Hi,
I bought a S4 yesterday but it needs a little (!!!) TLC

There is a whining only on load coming from either the diff or gearbox (or front diff also?)
There are 19" wheels on the car with three brands of tyres
i was wondering if this would contribute to the diff or transmission whine.

Would swapping the wheels around help me diagnose the problem i.e two individual tyres on back, matching ones on front?
Is there a way to measure the circumference of the wheels?

Also there is a lowering spring kit on the car which is too low and rides terrible!!!!
I was told they are H&R upgrades and are Black in colour can anyone tell me what make they might be i.e sport, Race etc.

I'm after a sprint/sport/OEM maybe Kit if anyone can recommend for everyday driving on B Roads

Many thanks
Steve Nick.

[Blue_Thunder]

There has been talk about running different tyres damaging diffs, but not sure how much truth there is in it. With three diffs and a gearbox there are plenty of suspects with regards to the whining. Guess you could eliminate the gearbox by seeing if the whine is apparent in all gears.

Are you sure the poor ride quality isn't down to the 19's rather than the suspension? If they are H&R springs, i've never heard anything negative about them. Have you checked that none of the dampers are leaking?

[NICNAC180579]

Cheers for the advice,
I'm fairly certain that the centre diff is the culprit! The whine starts to be audible about 30-40mph and comes roughly from the centre of the car.
I swapped the tyres around hoping that the noise would be transfered to the rear of the car due to un equal tyres but without success.

Am i right thinking the diff is an internal part of the gear box or not? If so i'm Going to buy a 2nd hand gearbox.
You're probably right about the shocks i didn't see any obvious leaks yesterday however its a good guess that the standard shocks are knackered as the car doesn't settle after a bump on the road.
Any suggestions for replacement shocks for comfort.
Thanks for your help
Steve.

[Blue_Thunder]

Yes the centre diff is inside the box. I think mine is knackered because it causes the car to kangaroo when coming off the throttle in low gears. Doesn't whine though.

From looking at the diagrams of the box it does look like the centre diff could be removed from the back end without dismantling the whole gearbox. Still, at upwards of £600 for a new one you want to be sure that it is the cause of the issue.

2nd hand RS4 suspension would be a fairly cost effective route to maintaining a comfortable ride. You could also swap your springs over if you weren't happy with the ride height.

[Dippy]

The whole point of diffs is to allow for different rates of rotation so there is no way that different tyres can cause problems here. A while back I did a thorough search on the subject and could find absolutely no evidence.

of course different tyres can affect grip & handling, but that's another matter.

My suspension is knackered and the car has just started to make a light whine (bit like wind noise) which sounds like it is coming from the rear. It is intermittent, and not engine related. I'm wondering if it is related to the suspension, so when I get it replaced fairly soon, I'm hoping the noise will have gone (if not I guess I might be checking this thread again).

[searider]

The wheel bearings on my S4 went within a year of each other and mad a noise that I thought was coming from under the car.

Check the easy stuff first!

[Blue_Thunder]

Wheel bearings would continue to make a noise even when there is no load on the engine.

[NICNAC180579]

I'm pretty sure its the Taper roller bearings in the front Diff in case anybody else is having the same problems:

4 and 6 in this:
http://www.vagcat.com/epc/cat/au/A4Q/19 ... 2/2809558/

My 1st and 2nd gears are notchy anyway so i was thinking i'll just buy a secondhand gearbox, diff included if anyone has one for sale PM me.
If a RS4 diff and gearbox fits my 1999 s4 saloon = even better!
Is the Gearbox an Engine out Jobby?

I took the car back to standard height which reduced the noise massively! However it is still there but not annoying anymore and so gives me time to source a 2nd hand part.
The symptoms are best described as a 'faint straight cut rally car gearbox' sound that begins 35-40ish mph and continues with a linear rise in pitch regardless of what ever gear you change to during acceleration
Cheers
Steve.

[stapo69]

Could it be knackered gearbox/diff mounts transfering more noise throuh the car?

I recently fitted apikol rear diff bushes and mount, they're a lot more solid than the standard ones and transmit more rear diff noise through the bodywork, so if any of your mounts are kaput and you have metal resting on metal this could cause more noise to appear to ome from them, even though they are just fine.

Just a thought.

[noccy]

I think it could be the wheel bearings also. When mine were giving up they only whined while taking bends. Worth checking as there not that expensive to fix!

[joshaudi]

Tapper roller bearings sounds right but i would also just check the wheel bearings anyway.

[weapon]

hi
i am breaking a complete year 2000 s4 and still have gearbox, diff , standard suspension, and pretty much anything else you might want, if you get to that stage, thanks