Drivetrain vibration, what to fix next?

[johnnymillers]

2013 B8 allroad, 155k miles, 2.0t, auto transmission

Issue:
Drivetrain vibration over the past few years, got worse in the past few months, recent work of replacing the engine mounts, front axles, and tire balance did not completely fix the problem. Should my next move be replacing the front control arm bushings/hardware? While driving the vibration can be inconsistent, but it’s pretty regular when accelerating, and it’s definitely always there when idling in drive with a foot on the brake, and goes away in neutral. Any thoughts on the control arms role in this?

History:
It started about two years ago with a local tire/oil change shop replacing front axles due to ruptured boots. I believe they went through three sets of axles and I eventually settled for a set that wouldn't cause a noticeable vibration under load, but the car still didn't feel perfect. Drove for about two years without much change but then the vibration started to get worse, and could be felt regardless of speed or loading, even when stationary in D with a foot on the brake. Shifting into N while stopped or moving would cause it to disappear. By the time I recently brought it to a better import shop the vibration had gotten pretty bad.

Recent work:
New axles (boots were torn), replaced the engine mounts (old ones were shot), balanced and rotated the tires, oil change, state inspection, etc. After the work the vibration was much less noticeable but definitely still there. The shop acknowledged that it's still there, and replaced the new right front axle at no charge, but with no result. The transmission mounts or fluids have not been replaced or serviced recently.

Currently:
On the highway it almost feels like an unbalanced wheel, but sharper, and it's there regardless of speed. It gets worse when accelerating, but is inconsistent (if I jump on it, sometimes I'll get a pretty severe wobble, other times not). While stopped, it completely goes away in N. On a cold morning it vibrates in park, and when physically touching the tires, it's definitely more noticeable in the front left. The vibration in park seems to go away after warming up.

Thanks very much!

[Raj1471]

Did you use OEM axles? The quality control of some aftermarket axles are lacking. I personally don't have firsthand experience using aftermarket just voicing the opinions I've read on this chat board and others. I replaced both front axles myself with a set of rebuilt axles from Raxles which came highly recommended from the chat boards. I would also replace the trans mount and service the trans fluid to see if that mitigates the vibration before leaning towards the axles. Also when was the last time the spark plugs were changed?

[Theiceman]

id read this over

https://www.blauparts.com/blog/audi-...8XEhZca294bQGU

[johnnymillers]

Did you use OEM axles? The quality control of some aftermarket axles are lacking. I personally don't have firsthand experience using aftermarket just voicing the opinions I've read on this chat board and others. I replaced both front axles myself with a set of rebuilt axles from Raxles which came highly recommended from the chat boards. I would also replace the trans mount and service the trans fluid to see if that mitigates the vibration before leaning towards the axles. Also when was the last time the spark plugs were changed?

The aftermarket axles that were installed two years ago by my local tire shop were definitely lacking. The recent axles were done by a reputable import shop, and he already changed one of those out for me at no charge, which did nothing to fix the vibration. At this point I’m not going to pay for another set of axles and he’s not going to install anymore for free. I’m ok living with the current axles and looking at the transmission and/or control arms.

Do you suggest transmission first, or the bushings/hardware on the front control arms? My guy at the import shop is leaning toward the control arms being the next thing to service, and has not mentioned the trans.

Thanks

[MetalMan]

At this point I don't know how it can be related to axles based on this:

vibration started to get worse, and could be felt regardless of speed or loading, even when stationary in D with a foot on the brake.

And this:

On a cold morning it vibrates in park

When stopped in Drive, the only thing the axles do is apply braking torque on the transmission. They can't cause vibration without themselves rotating. And rotational vibration from axles is very likely to vary with speed.
Also for a similar reason I don't think it's the center support bearing.

This is what's intriguing me:

Shifting into N while stopped or moving would cause it to disappear

So this leads me to believe the vibration is load-dependent. And I'm leaning toward something on the transmission side... I'm less familiar with auto transmissions but wondering if it might be related to the torque converter, though the vibration occurring in Park doesn't necessarily support this.

I think it's worth replacing the transmission mount next, it sucks firing the parts cannon, but this is a relatively easy part to replace.
And while in that vicinity it might be good to do transmission fluid/filter change (trans mount comes off for this service) if it's been a while. ZF seems to indicate 50-75k mile intervals for this service FYI.

[johnnymillers]

At this point I don't know how it can be related to axles based on this:

And this:


When stopped in Drive, the only thing the axles do is apply braking torque on the transmission. They can't cause vibration without themselves rotating. And rotational vibration from axles is very likely to vary with speed.
Also for a similar reason I don't think it's the center support bearing.

This is what's intriguing me:

So this leads me to believe the vibration is load-dependent. And I'm leaning toward something on the transmission side... I'm less familiar with auto transmissions but wondering if it might be related to the torque converter, though the vibration occurring in Park doesn't necessarily support this.

I think it's worth replacing the transmission mount next, it sucks firing the parts cannon, but this is a relatively easy part to replace.
And while in that vicinity it might be good to do transmission fluid/filter change (trans mount comes off for this service) if it's been a while. ZF seems to indicate 50-75k mile intervals for this service FYI.

Thanks! This was very helpful. The vibration in Park was strange and maybe it was just a rough idle that morning, but I definitely felt a noticeable vibration when physically touching the front left tire that was not as bad on the other three. The car warmed up and it went away, and has not been there the past few cold mornings.

The vibration while stopped with a foot on the brake in Drive is definitely consistent, and definitely goes away when you shift into neutral. So it's load-dependent for sure.

Excuse my ignorance, would this bushing kit help? or is it more complicated?

https://www.ecstuning.com/b-ecs-part...BoCDXwQAvD_BwE

[MetalMan]

Thanks! This was very helpful. The vibration in Park was strange and maybe it was just a rough idle that morning, but I definitely felt a noticeable vibration when physically touching the front left tire that was not as bad on the other three. The car warmed up and it went away, and has not been there the past few cold mornings.

This might be pertinent information. I'm wondering if that was perhaps unrelated (or less-related) and from a soft misfire due to the extra cold temperature on that day. Do you know the age of your spark plugs and ignition coils? And have you by chance checked for ECU fault codes? There could be misfire codes even without a CEL (check-engine light).

The vibration while stopped with a foot on the brake in Drive is definitely consistent, and definitely goes away when you shift into neutral. So it's load-dependent for sure.

Without having the car at my fingertips, I can really only suggest "firing the parts cannon" as you've already done a bit. This is my suggested approach:

• trans fluid/filter (you didn't mention last interval)
• you take off the trans mount to drop the trans oil pan, so change trans mount while in there
• check ignition system, spark plugs and coil packs. if you don't know when spark plugs were last changed, it's quick, easy, and not too expensive to change them out.

Excuse my ignorance, would this bushing kit help? or is it more complicated?

https://www.ecstuning.com/b-ecs-part...08288ecs01kt1/

Somebody else will have to answer, I'm not that experience with this aspect of the B8.

[johnnymillers]

I very much appreciate all the insight, MetalMan. I can't remember when the transmission was last serviced, it's been a while.

The coil packs and spark plugs were changed in April of 2023 (26K miles ago) when I had the shop do an oil system chemical soak and flush. This miraculously solved the common 2.0t oil consumption issue that was about to be a deal breaker for me and this car. On separate occasions this oil issue probably caused a burnt exhaust valve, and misfires due to cylinder compression issues. After this soak, new coil packs and plugs, the cylinders all performed well in their leak down and compression tests, and I've had very little oil consumption. I will change the spark plugs.

Here's one last bit of info before I go to work on the transmission:

This morning was another cold start and the vibration in Park was back. The whole car was noticeably shaking in Park, but it completely went away when I shifted into Neutral. No matter the conditions (stopped/highway/cold/hot) the engine and drivetrain is perfectly smooth in neutral. What could cause an inconsistent vibration in Park but never in Neutral?

[MetalMan]

Sounds like coils and plugs shouldn't be an issue. But I'll ask again, any stored fault codes?

Man that is strange regarding park vs neutral. I always thought the engine is in the same loaded condition in park & neutral. i.e. no load, engine is effectively decoupled from any driven gear. I believe the only difference between park & neutral should be the parking pawl in the transmission is engaged in park.

So maybe let's dive in on the parking pawl a bit. When you're in park with the vibration, is the car level or on an incline? Do you have the parking brake engaged? If yes, does the vibration in park change if the parking brake is disengaged?
If the car is parked level (no incline) with parking brake off, try rolling the car back-and-forth to get it so it's not resting on the parking pawl. Does that change the vibration?

I'm unsure where the answers to these questions will lead us but let's find out.

[4xaudi]

I had a vibration devloping in my 2013 allroad with 220k on it. Changed the transmission fluid and filter and it went away. I think what your feeling is torque converter shudder.

[MetalMan]

I had a vibration devloping in my 2013 allroad with 220k on it. Changed the transmission fluid and filter and it went away. I think what your feeling is torque converter shudder.

My first post in this thread mentioned wondering if it could be related to torque converter. In my subsequent post the top item of my "suggestions of things to do" list was fluid/filter change.
Sounds like @johnnymillers has a viable path forward

[johnnymillers]

Thanks, guys. Did some more testing of the vibration in Park: It's there when parked on a slight incline, but not on flat ground. So it seems that resting on the pawl causes it to be felt throughout the car. There's still no vibration in Neutral, regardless of incline/flat or parking brake set/released.

Also, no stored codes. And, I forgot to set the parking brake when in Park on an incline or flat, but I will and see if that makes any difference.

Definitely going to start with the transmission service and mounts.

[Shane Horning]

What engine mounts did you install?

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[johnnymillers]

good news: mechanic had it up on the lift in drive and holding the brake, could easily see and feel the transmission vibrating. seems very likely the transmission mount is the issue.

bad news: rear subframe is crumbling like a dry croissant.

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[Theiceman]

well....... that looks expensive..

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[A4Qwattro]

It's a good idea to buy a can of fluid film or cavity wax with a cavity extension and bathe the inside of the subframe on a car which still had an in-tact subframe. Had Audi done this from the factory, these subframes wouldn't get so bad. But that cost money and Audi doesn't care about these cars falling apart outside of warranty.

[johnnymillers]

Update on the vibration:
I changed the transmission mount with a new factory part from the dealership, maybe a slight improvement on the highway, but it’s still there when idling in drive, reverse, and sometimes park. As I took the old one out I was discouraged at how much it resembled the new one, some corrosion on the metal but the rubber looked fine.

When stopped, it vibrates more in drive and reverse than in park, and the vibration in park is only noticeable when the car’s weight is on the transmission; you don’t feel it on flat ground, or when setting the parking brake before shifting into park.

When stopped in drive, reverse, and sometimes park, you can physically feel the front tires vibrating when touching them. Hardly at all in the rear tires.

No matter what speed, the car is smooth in neutral.

Next up is a transmission service, and the rear subframe.

[Theiceman]

torque converter

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[RPMtech147]

Did you use OEM axles? The quality control of some aftermarket axles are lacking. I personally don't have firsthand experience using aftermarket just voicing the opinions I've read on this chat board and others. I replaced both front axles myself with a set of rebuilt axles from Raxles which came highly recommended from the chat boards. I would also replace the trans mount and service the trans fluid to see if that mitigates the vibration before leaning towards the axles. Also when was the last time the spark plugs were changed?

This. Aftermarket axles are garbage. I just went through this with a client with an SQ5.

[A4Qwattro]

With these cars, rebuild your OEM axles or get replacement OEM axles. Has been the case with Audi forever. No one knows how to make aftermarket.

[johnnymillers]

I’ll second that the OEM axles are the way to go. I went through two or three sets a few years ago when I had a basic oil change shop change them. They couldn’t get a good set, and I was so fed up I just settled for minor vibrations.

The recent work I had done did replace the axles again, and despite not being OEM or raxles, I don’t think that is causing my vibration issue. This is a different type of vibration than I felt with the bad axles, and it’s there with no rotation at all, which was not the case before.

My next move is the transmission fluid service, which will be the first trans service (to my knowledge) and I’ve had the car since 36K. A quick search on the torque converter replacement yielded expensive results, so I’m hoping that is not the culprit.

[A4Qwattro]

I’ll second that the OEM axles are the way to go. I went through two or three sets a few years ago when I had a basic oil change shop change them. They couldn’t get a good set, and I was so fed up I just settled for minor vibrations.

The recent work I had done did replace the axles again, and despite not being OEM or raxles, I don’t think that is causing my vibration issue. This is a different type of vibration than I felt with the bad axles, and it’s there with no rotation at all, which was not the case before.

My next move is the transmission fluid service, which will be the first trans service (to my knowledge) and I’ve had the car since 36K. A quick search on the torque converter replacement yielded expensive results, so I’m hoping that is not the culprit.

Have you checked motor mounts? iirc, the motor mounts are active and designed to damp out a resonance that occurs with the torque converter cars at idle when you are in drive, and holding the brakes. Not an issue with manual cars.

[Theiceman]

but its vibrating he says parked if i read it correctly...

" but it’s still there when idling in drive, reverse, and sometimes park."

if this is true .. its not the axles....

[A4Qwattro]

It's probably still the motor mounts if no misfires are being logged.

[johnnymillers]

No misfires, but the motor mounts and the transmission mount were changed recently. I did the trans mount myself, and the motor mounts were replaced along with the axles back in November by a reputable import shop. When I brought it to the shop the vibration was pretty bad and it was better after the work, but not completely gone.

[DanielHamilton]

I know you said the motor mounts were done, but this sure sounds like bad motor mounts. Possible they put the wrong ones in? Hard to see how it could be anything else.

The trans fluid service isn't too bad, I did it last year. But it didn't really change anything for me. (Probably because the vibration is coming from my motor mounts, which I still haven't changed.)

[johnnymillers]

Update: Transmission fluid replaced and mount replaced = still vibrating! The car shakes when stopped in gear and foot on the brake, and you can physically feel the front tires vibrating if you touch them. Everything is smooth in neutral no matter what speed. When accelerating I can get the car to shake, but it’s inconsistent. It happens at different speeds and different amounts of load. The feel is different than an unbalanced wheel or a bad axle, it feels like its coming from the front center of the car like the trans or the engine.

At this point it seems like it's either a motor mount or torque converter.

Motor mounts - both were changed recently (as well as both axles) and reduced the vibrations, but didn't eliminate it completely.

Torque Converter - from what I've read/heard this seems like it could cause the vibration I feel when stopped in gear, but there is no bucking/irregular shifting of gears automatically or with the paddle shifters. There are also no RPM fluctuations.

Is there a way I can trouble shoot either of these on my own?

Thanks!

[Shane Horning]

I had asked earlier what eng mounts were installed. Curious if they were solid ones?

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[johnnymillers]

Sorry, I meant to answer the motor mount question earlier. According to the shop, the new mounts are "smart" mounts. The explanation was that there are smart and dumb mounts, the smart being the fluid filled with sensors, and the dumb are just solid rubber. I'm not sure what brand. Parts were $365 for the passenger side and $297 for the driver, total cost was just over $1,000. Work was done in November and it did noticeably reduce the vibrations.

Is these alleged smart mounts were having issues, would they throw a code?

[Shane Horning]

Sorry, I meant to answer the motor mount question earlier. According to the shop, the new mounts are "smart" mounts. The explanation was that there are smart and dumb mounts, the smart being the fluid filled with sensors, and the dumb are just solid rubber. I'm not sure what brand. Parts were $365 for the passenger side and $297 for the driver, total cost was just over $1,000. Work was done in November and it did noticeably reduce the vibrations.

Is these alleged smart mounts were having issues, would they throw a code?

Ok those should be fine, the solid ones cause vibration

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