2017 S3 weird noise from rear

[ausaudis3]

Hi all,

Recently got some new tyres fitted for my S3, had an alignment done also, did about 200k’s before I started getting this weird sound coming from what seems to be the rear left.

Had the dealer rotate tires and replace them with new ones and sound didn’t move/change.

noise starts as a whine almost aeroplane like at 60kph and gets louder, won’t go away until I come to a stop and on decel under 15kph I get the below sound

https://vimeo.com/1053343010?share=copy#t=0



Any ideas what it might be? Had a passenger in the rear with the seats down and they are sure it’s coming from the left hand rear side

[MikTip]

Sounds like wheel bearing...

[o1turbo30v]

Sounds like wheel bearing...

this^

[ausaudis3]

this^

Took it in today and tech said it doesn't sound like a wheel bearing and he thinks its the rear diff.

Quote for the work is not cheap, looking at 4-5K AUD for a second hand with Haldex to be installed.

He won't know for sure until it goes on the lift Monday.

Going to try and get a second opinion tomorrow

[MikTip]

Took it in today and tech said it doesn't sound like a wheel bearing and he thinks its the rear diff.

Quote for the work is not cheap, looking at 4-5K AUD for a second hand with Haldex to be installed.

He won't know for sure until it goes on the lift Monday.

Going to try and get a second opinion tomorrow

Rear diff....how much oil is in it and are metal pieces in the oil...that will tell in 2 seconds whats going on with the rear diff. The haldex is removable/ seperate. Plenty of used low mileage rear diffs out there .
www.car-parts.com

[ausaudis3]

Rear diff....how much oil is in it and are metal pieces in the oil...that will tell in 2 seconds whats going on with the rear diff. The haldex is removable/ seperate. Plenty of used low mileage rear diffs out there .
www.car-parts.com

Yeah that’s the plan for Monday, get it on the lift and see how sparkly the fluid is, if there is any

Looking at the last major service they mention haldex fluid changed by nothing for diff so likely never been done

Found a decent final drive with the haldex for $2k AUD, likely another 2k installed. Lower mileage too so will likely use that haldex to save future problems down the road

[949]

how many launches have you done on it?

[ausaudis3]

how many launches have you done on it?

Myself, none, previous owner..unknown.

I've tried looking in OBDeleven for it but cant locate it, not sure if its something you can see on a 2017 FL S3

[ausaudis3]

Well it looks like my diff decided to turn into a glitter sparkle generator.

Got it drained today and in the glitter was some bearing material from the look of it.

Second hand diff and Haldex on the way hopefully won't take too long to go in.

Going to get them to change the fluid in the front transfer case while its up there as i don't think they ever got done as its "sealed for life" and not on the Audi service schedule.

[MikTip]

Well it looks like my diff decided to turn into a glitter sparkle generator.

Got it drained today and in the glitter was some bearing material from the look of it.

Second hand diff and Haldex on the way hopefully won't take too long to go in.

Going to get them to change the fluid in the front transfer case while its up there as i don't think they ever got done as its "sealed for life" and not on the Audi service schedule.

Yah...that sealed for life is garbage!

[ausaudis3]

well the fun continues.


Rear diff installed and the about 20% of the noise is gone, they finally took my advice to run it on the lift and listen for it, Noticed its coming from the transfer case.

Took it into another mechanic and they straight away ran it on the lift and got out the stethoscope and yep, confirmed its coming from the transfer case.

Drained the fluid and it also looked like 90's ski boat paint, glitter and flakes everywhere.

New case goes in next week, and another chunk of money leaves my wallet :(

[MikTip]

Yah...I had to replace my motor...cause VW/Audi had a known piston ring issue. After 297728 km...my engine drank a quart of oil a day...

Found a used motor with 7621km and DIY installed it.

My 2015 S3 currently has 341180km on it and the DSG is showing its age...but I have a low mileage replacement DSG awaiting install.

They dont build cars to last anymore...

[texasboy21]

well the fun continues.


Rear diff installed and the about 20% of the noise is gone, they finally took my advice to run it on the lift and listen for it, Noticed its coming from the transfer case.

Took it into another mechanic and they straight away ran it on the lift and got out the stethoscope and yep, confirmed its coming from the transfer case.

Drained the fluid and it also looked like 90's ski boat paint, glitter and flakes everywhere.

New case goes in next week, and another chunk of money leaves my wallet :(

What are you referring to as the transfer case? The front 'bevel box'?

[ausaudis3]

What are you referring to as the transfer case? The front 'bevel box'?

Yeah bevel box/transfer case/front diff whichever you want to call it.

[ausaudis3]

It’s a shame, everything else about the car is rock solid, body and paint are mint, engine and DSG don’t skip a beat.

Honestly even if I had to replace both of those, basically the entire driveline, I would as these cars are imo one of the best bang for buck performance cars you can get

[MikTip]

It’s a shame, everything else about the car is rock solid, body and paint are mint, engine and DSG don’t skip a beat.

Honestly even if I had to replace both of those, basically the entire driveline, I would as these cars are imo one of the best bang for buck performance cars you can get

So I am curious why the two differentials would go bad?

On my 2015 S3 I have 341180km and both diffs are still issue free...

[ausaudis3]

So I am curious why the two differentials would go bad?

On my 2015 S3 I have 341180km and both diffs are still issue free...

Feel like the previous owner launched the sh!t out of it.

I’ll know what failed as I’m getting both the rear and front diff from the shop to pull apart and see what went wrong, if it’s just a bearing I’ll likely clean them up, replace the bearing and hold onto them just incase any future issues

[texasboy21]

Yeah bevel box/transfer case/front diff whichever you want to call it.

Thanks! Ive noticed some noise/growl as well, but I am on my third fluid fill at 80k so I think it may be a wheel bearing.

[TreizeRXH]

Sounds like wheel bearings. My rear wheel bearings were shot around 70k miles. They're a strange early failure point on these cars (I've never had wheel bearings go with such low mileage). I fixed it myself, but I will say it was a real b*tch of a job to do. I understand why shops charge so much for the work, but I decided it was still worth tackling the work myself if I was only paying $270 for parts vs a few grand at a shop.

Good news is, the car runs great now. Do what works best for you.

[texasboy21]

Sounds like wheel bearings. My rear wheel bearings were shot around 70k miles. They're a strange early failure point on these cars (I've never had wheel bearings go with such low mileage). I fixed it myself, but I will say it was a real b*tch of a job to do. I understand why shops charge so much for the work, but I decided it was still worth tackling the work myself if I was only paying $270 for parts vs a few grand at a shop.

Good news is, the car runs great now. Do what works best for you.

I was under the impression the bearings are bolted in (as opposed to being pressed in) and fairly simple to swap.. how was your install?

[TreizeRXH]

I was under the impression the bearings are bolted in (as opposed to being pressed in) and fairly simple to swap.. how was your install?

Yes they are bolt in, but you have to basically pull everything out to get to them (and then they are torqued crazy tight so it was a b*tch and a half to get the bolts to free up)