sonar

hi folks!

long time lurker here. drove an 01 S4 for 12 years until i recently picked up a 2013 6MT. loving the supercharger.

as many of you know, this car has a distinctly different sound than the old biturbo. i've grown accustomed to what i can only seem to articulate as a chainlike click-click-clicking at parking lot speeds that reminds me of the sound of a roller coaster going uphill. i've recently realized that this sound is only present while in gear; revving the engine in neutral does not create that sound. i thought it was the supercharger but that data point suggests otherwise.

my concern is: that sound i describe above seems to have gotten a little (but noticeably) louder recently and i am wondering if i need to STOP DRIVING IMMEDIATELY or if it's a thing i can have looked at in 3k miles when i go in for my 70k service.

the reate/period of the sound is dependent on vehicle speed, but the frequency/pitch seems to be about the same. once the car is above 30mph, it either stops making the noise or i can't hear it over road noise etc.

any information or advice greatly appreciated!!! i'm owner #3; second owner bought it CPO 16 months ago and added APR stage 1 upgrade, and it is still under CPO warranty. i am trying to determine if i need to rush off to get a factory reflash and make a stealership appointment if this might be a known issue that would be covered under CPO warranty.

thank you nice people!!!!

togatown

So it only makes a sound when you are moving? Does it vary when you turn side or only make noise when you are going straight? The Quattro system does sometimes make some funky sounds at very low speed when turning, but what you are describing does not sound normal since it appears to be happening while driving.

sonar

hi togatown

it is not the turning click-click. i remember that sounds from the 01. this sound is consistent while traveling straight.

Bobby Kinstle

How's your tire condition? My last set sounded like a failing wheel bearing when they got too thin.

Also possibly a wheel bearing.

togatown

If it changes pitch/sound when you turn side to side at speed, that would lend itself to a wheel bearing. B8-8.5 S4 wheel bearing issues are common.

sonar

hello again

tires are healthy. sound does not seem to be dependent on steering direction.

today i drove it slowly down an alley in my neighborhood so i could hear it better. the sound is very, very noticeable at low speed, and immediately stops when i push in the clutch.

any chance that's a useful hint?

thanks!

togatown

If it stops making noise when coasting in neutral or with the clutch disengaging the drive train, definitely need to get that checked out. Sounds like a tranny or sport diff issue, maybe even motor mount failure?

sonar

follow up for closure:

the dealer suspected the clutch bearing. since the car is still under CPO, work was covered. they offered to replace the clutch & flywheel for the cost of parts while the transmission was out, so i did that.

they got the car back together and the noise was still there!

techs diagnosed the sound as coming from inside the transmission and not considered serviceable, so they replaced the whole transmission, covered under CPO thankfully. i was told that would have been an $11k job!

i was extremely surprised that it was the transmission; everybody i spoke with that has some technical background with audi seemed confident that the transmissions are bulletproof. i don't know if the previous owners abused it or if it was just a fluke.

Evan's Santorin S4

Thanks for the follow up.

DrGP

I would be leaning toward wheel bearings. Very common for them to go out in these cars. BUT, I thought I had a wheel bearing problem and it was actually the tires. How many miles do you have on the tires. Many tires get very loud when they get down to the last 1/3-1/4 of tread