[enjikari]

Hello folks. Bringing this to the forums a few days before I bring my ride back to the dealership. I'm hoping someone knows a good fix that I can perform, or can at least tell me things to look at/try on my own - in case my extended warranty doesn't cover this.. whatever it is.

Stock 6gen, just shy of 69k miles. This issue has been present for about the last 3 or 4 months or so. Just had new tires put on last month, so not the tires. The issue us: when I'm going in the neighborhood of 71-74ish MPH, I hear this fairly loud rattling sound, seemingly coming from the FWD passenger area. Happens if I'm accelerating/steady on my own, and if it's on cruise control. If I go above or below that, it goes away. The rattling... hard to say what it sounds like but, it's slightly hollow sounding and almost like someone was holding a drill up against some sheet metal. Like a steady-frequency vibrating, not like a rock bouncing in a can.

I brought her in to the dealership. I'm under an extended warranty for another 30k or so. They had it for less than a week. The 'fix' they sent her home with was: they found an electrical plug that controls something with the exhaust system unplugged. They said that the car, at that MPH, was constantly trying to perform some exhaust control and it couldn't because the plug was unplugged, so that is what was making the rattling happen under those parameters.. I was very skeptical, but they assured me it was good now. I paid my ~$200 and took her home. I hit 72ish off and on during that drive home, and sure enough didn't hear it. Well today, I'm hearing it again. Happened 3 or 4 times, every time I was hitting that MPH range. I called them back and told them about it, said I'd be bringing it back in this THU. I wanted to run it by you fine folks before I did though.

Clearly I don't know what the issue is. I haven't done much except jack her passenger FWD side up and look around (without taking the tire&wheel off) but I didn't see or feel anything loose. The fact that I don't know if this issue will be covered under my ExtW is why I'm humbling asking for help/advice here. I'd hate for this to be laboriously troubleshot and fixed, not covered, the culprit at the end of the day is, like... "found bent metal corner under XXXX, bent corner, good to go - here's your $800 bill".

Let me know what you think folks. I'm open to advice and suggestions. And I'll provide updates. Please, kindly, and thank you.

[CalgaryZL1]

Faulty wheel bearing? Is it like a harmonic vibration at certain speeds?

[enjikari]

Originally Posted by CalgaryZL1

Faulty wheel bearing? Is it like a harmonic vibration at certain speeds?

What can I do to check if it's a faulty wheel bearing? I'm assuming jack the right side up and take off the wheel, but what should I be looking for/how can I test the wheel bearing once the wheel is off?

And yes. It only happens 71ish-to-74ish MPH. If I;m going down the interstate and set the cruise to 72 (which is what I normally set it to) it's present. Yes, it's a harmonic, steady-frequency rattling, like someone drilling into sheet metal. Not a clanging, not a clunking, not an infrequent rattling like a rock in a can.

[arpad_m]

I experienced something similar when a wheel/tire combo could not be perfectly balanced no matter what the dealership and a separate tire shop tried, I had to change both for it to go away eventually.

Not saying this definitely is your problem, but it's a possibility, especially since you're only experiencing it in a narrow speed range.

[enjikari]

Originally Posted by arpad_m

I experienced something similar when a wheel/tire combo could not be perfectly balanced no matter what the dealership and a separate tire shop tried, I had to change both for it to go away eventually.

Not saying this definitely is your problem, but it's a possibility, especially since you're only experiencing it in a narrow speed range.

Hmm.. I'll add it to the list of things to consider, but I did just put new tires on the same wheels about a month ago, and I've had the issue before and after the tire change.

[FlukeSS]

Originally Posted by enjikari

Hello folks. Bringing this to the forums a few days before I bring my ride back to the dealership. I'm hoping someone knows a good fix that I can perform, or can at least tell me things to look at/try on my own - in case my extended warranty doesn't cover this.. whatever it is.

Stock 6gen, just shy of 69k miles. This issue has been present for about the last 3 or 4 months or so. Just had new tires put on last month, so not the tires. The issue us: when I'm going in the neighborhood of 71-74ish MPH, I hear this fairly loud rattling sound, seemingly coming from the FWD passenger area. Happens if I'm accelerating/steady on my own, and if it's on cruise control. If I go above or below that, it goes away. The rattling... hard to say what it sounds like but, it's slightly hollow sounding and almost like someone was holding a drill up against some sheet metal. Like a steady-frequency vibrating, not like a rock bouncing in a can.

I brought her in to the dealership. I'm under an extended warranty for another 30k or so. They had it for less than a week. The 'fix' they sent her home with was: they found an electrical plug that controls something with the exhaust system unplugged. They said that the car, at that MPH, was constantly trying to perform some exhaust control and it couldn't because the plug was unplugged, so that is what was making the rattling happen under those parameters.. I was very skeptical, but they assured me it was good now. I paid my ~$200 and took her home. I hit 72ish off and on during that drive home, and sure enough didn't hear it. Well today, I'm hearing it again. Happened 3 or 4 times, every time I was hitting that MPH range. I called them back and told them about it, said I'd be bringing it back in this THU. I wanted to run it by you fine folks before I did though.

Clearly I don't know what the issue is. I haven't done much except jack her passenger FWD side up and look around (without taking the tire&wheel off) but I didn't see or feel anything loose. The fact that I don't know if this issue will be covered under my ExtW is why I'm humbling asking for help/advice here. I'd hate for this to be laboriously troubleshot and fixed, not covered, the culprit at the end of the day is, like... "found bent metal corner under XXXX, bent corner, good to go - here's your $800 bill".

Let me know what you think folks. I'm open to advice and suggestions. And I'll provide updates. Please, kindly, and thank you.

Could also be Transmission shudder. For me it was at 48-52mph, and 70-72mph on my 2016 SS. Quick test: When you hear it at that speed give it firm gas pedal enough that it downshifts quickly and rpms rev up higher see if it clears up at higher rpm's. If it does, its more than likely transmission shudder known to be an issue on A8's. Worst case scenario if you drove on it too long, you'll need a new Torque converter and a transmission fluid change.

https://static.nhtsa.gov/odi/tsbs/20...63890-9999.pdf

[enjikari]

Originally Posted by FlukeSS

Could also be Transmission shudder. For me it was at 48-52mph, and 70-72mph on my 2016 SS. Quick test: When you hear it at that speed give it firm gas pedal enough that it downshifts quickly and rpms rev up higher see if it clears up at higher rpm's. If it does, its more than likely transmission shudder known to be an issue on A8's. Worst case scenario if you drove on it too long, you'll need a new Torque converter and a transmission fluid change.

https://static.nhtsa.gov/odi/tsbs/20...63890-9999.pdf

So I'm not leaning towards that shutter, mainly because she's been in four separate times for the actual shutter I had and she has 1) a new tranny 2) a new torque converter and 3) new fluid. Plus, this doesn't sound like the shutter, which I know that sound AND the feeling, from when it was occurring.

She's in the shop now, but I did take two videos to help capture the sound. Have a listen, forum friends, and see if this sounds familiar to any of you OR if you may know where I can inform them to look, if they call me for more feedback:

https://youtube.com/shorts/Q9y5WmD7SME?feature=share
https://youtu.be/rNDWHy1D61Q

[FlukeSS]

Originally Posted by enjikari

So I'm not leaning towards that shutter, mainly because she's been in four separate times for the actual shutter I had and she has 1) a new tranny 2) a new torque converter and 3) new fluid. Plus, this doesn't sound like the shutter, which I know that sound AND the feeling, from when it was occurring.

She's in the shop now, but I did take two videos to help capture the sound. Have a listen, forum friends, and see if this sounds familiar to any of you OR if you may know where I can inform them to look, if they call me for more feedback:

https://youtube.com/shorts/Q9y5WmD7SME?feature=share
https://youtu.be/rNDWHy1D61Q

Ok ya that's definitely not shudder.

Does it stop when you let off the gas or get on it?

Sounds almost like mid-pipe rattle like a loose brace?

[enjikari]

Originally Posted by FlukeSS

Ok ya that's definitely not shudder.

Does it stop when you let off the gas or get on it?

Sounds almost like mid-pipe rattle like a loose brace?

So sorry fort he late reply. So I do believe that when I come off the gas pedal it goes away, but I can't 100% recall if that's solely because I got off the gas pedal or because the speed/RPMs drop(ped). And she's still in the shop, so I can't test it. I'm just keeping my fingers crossed. Mainly because I hope whatever they find will be covered under my extended warranty. And also, whatever they find they are able to administer a permanent fix.