Vibration from the diff?

[DAZ1985]

I have a vibrating noise from the diff (sounds like its dragging) when in first gear on full lock?

I have changed the diff oil (used genuine Audi stuff)

Made no difference

Seems to get louder when it's warm after a long journey

If the diff is shot would a diff off an allroad a6 fit?

[Turkster]

all i know about diffs is its best to change "like 4 like" as they can off set your speedo and quattro set up,

[towcestervag]

they all do it
test drive another but they all make a noise on full lock pull away

[DAZ1985]

It's the same engine, just auto on the allroad mines manual, but I'll take that on board. Thanks

[olly quattro]

They defo all do it

[DAZ1985]

Seems strange they all do it, sounds wrong.

Is their a reason why? Or should I stop worrying about it and accept it how it is?

[towcestervag]

its the diff winding up
it working hard when on full lock
if you think 1 wheel is nearly stationary and the other is moving quite a distance so the diff is working at its optimum hence the noise
been with audi since the original quattro and before and they have all made this noise
So dont worry!

[DAZ1985]

Reason I ask is me dads s3 doesn't make the same noise, nothing like it

[jbcalvin]

4WD drive system on the S3 is totally different to the A4, S3's are FWD until slip happens and then power sent to the back using the haldex system......

A4's use old school permanent 4WD with torsen front/centre/rear mechanical diffs which are pretty much bombproof, worked for VAG for over 10 years, never saw a diff failure......

[quattro tony]

I know the s3 doesnt have the same diff as the a4. The s3 has a haldex which only sends power to the rear wheels when required so most of the power is sent to the front in normal conditions.How old is ur dad's s3 btw?

[DAZ1985]

If you all it's fine I'll go with that

S3 on a 59 plate tony

[quattro tony]

If you all it's fine I'll go with that

S3 on a 59 plate tony

S3 still should be a haldex as mentioned above. I would go test mine and report bk but i carn't as ive just traded my a4 quattro in , i think mine did it on full lock aswell.