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2018 Outback 2.5 Limited w/ Eyesight - Magnetite Gray
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Discussion Starter · #1 ·
Hello - I had posted about this issue in someone else's thread, but it was only semi-related so I wanted to start a new thread specifically addressing this issue.

I have a light harmonic vibration that you can feel in the wheel, seat, console, etc. It isn't a violent vibration, but rather a buzz of sorts. It seems speed sensitive, not engine RPM sensitive. On perfectly smooth roads it seems to present itself between 60 & 80 mph. Dealer has road force balanced tires, checked alignment, and all of the usual troubleshooting. Same vibration with my new winter wheels & tires (also road force balanced).

The only way I've found to document the issue is to record a water bottle in the console or door pocket.

I'm posting 4 videos to see if you all think it is normal - maybe I'm being too picky. Do your beverages shake? Thanks for taking a look.

 

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2018 Touring 3.6R
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The only vehicle in my garage that shakes like that is a 14yo diesel truck with 330k miles. Considering yours has done it through two sets of tires/wheels pretty much means it's axle, driveshaft, differential, transmission/transfer case. Good luck with that.
 

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2018 Outback 2.5 Limited w/ Eyesight - Magnetite Gray
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Discussion Starter · #5 ·
The only vehicle in my garage that shakes like that is a 14yo diesel truck with 330k miles. Considering yours has done it through two sets of tires/wheels pretty much means it's axle, driveshaft, differential, transmission/transfer case. Good luck with that.
Ha, I think that is why I'm so frustrated. Basically being told that nothing is wrong and the reverberations (their word, not mine) are normal - "move along, nothing to see here" kind of thing. Our other car is a Toyota approaching 200k miles with no issue like this; my last several cars have been Subaru and Toyota with no buzz in the chassis.
 

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2017 Outback 2.5i Limited, Twilight Blue/Ivory
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273 Posts
My 2017 doesn't do this. Went out for a drive today and had a water bottle like yours in the cupholder and on smooth roads there wasn't any steady vibrations. I'd occasionally drive over some ripples in the road that caused vibrations but on perfectly smooth roads there wasn't a hint of any vibrations at all.
 

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We had a new 1998 Ford Expedition with harmonic like vibrations. Many folks were changing out drive shafts, putting harmonic balance weights on the rear axle etc. etc., to no avail. The dealer did install a balance weight on the rear axle, but this did not fix the issue. I ended up just loosening the exhaust bolts, letting the system equalize and torqueing the bolts again. The vibrations went away completely. Your case may be different, but I caution against letting the dealer start replacing components as you will most likely be frustrated chasing a moving target. There could be some stress in your system (suspension, drive train, exhaust). A simple realignment could fix it; yes, I realize the dealer "checked" the alignment and found it OK.
 

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2018 Outback 2.5 Limited w/ Eyesight - Magnetite Gray
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Discussion Starter · #8 ·
Thanks for the feedback novasquid - I believe it is hit or miss as my brother-in-law's does not have the issue either.

abb4430, all good info - thanks. On my last Outback, the exhaust hanger that bolts to the transmission broke and had to be replaced. I went under the car and took a look - everything looks normal there, but otherwise I think there are only 3 rubber hangers holding the exhaust up (other than the header)? Agreed about the dealer "checking" things like alignment. I'm starting to lose faith that they even care enough to spend time hearing my concerns.

I do have a great shop nearby that I usually go to for tires (one of Tire Rack's top rated local installers) and alignments. I am thinking of taking it there to have the balance and alignment checked/adjusted even if I have to pay for it... just to make sure that I have everything covered before doing anything drastic.

Thanks again for the continued feedback everyone.
 

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I have what seems to be the same issue. I drove the car for the first time yesterday and noticed it, around 70ish mph. I thought it was something related to the CVT/Transbrake or something... I need to get more seat time before forming an opinion.
 

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Hey,

I have the same strange vibrations but on lower speeds. Problem is that from the steering wheel to the seats and head rests everything is rattling.
Took it to the dealer already and they don't see any issues.

We had a 2016 Modell in OZ for around 35k and I never had any vibration or rattling.

I'm super disappointed right now...

Next weekend I gonna check it myself, maybe there is something loose.

BTW: Problem was getting worse since they changed to winter tires.

Cheers
 

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2018 Outback Limited 2.5i and 2018 Audi A4
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These problems are tough to find. The best way to do it is to measure the frequency of the vibration and then start computing what runs at that speed. At about 70 mph the tires rotate about 10 rotations per second. I do not know the rear axle ratio on the Outback but assume it is 3.9:1 which is typical of many cars. Then the driveshaft is rotating at about 39 revolutions per second. If the tranny is 1:1 at 70 then then engine is also running 39 revolutions per second. If you have a 3.6 there are three combustion’s per rotation for a firing rate of 117/sec, if it is a 4 cylinder then you have 78/second. Hopefully now you get the idea. So you need to measure the vibration frequency and knowing the characteristics of the car do some math and figure out what matches the vibration. Automakers do this stuff all of the time. Dealers typically are not smart enough to figure this out.

I happen to be familiar with this because I sell an iPhone app called Vibration which is used by some auto makers and tire makers to look for problems like this. The iPhone can measure up to 50 cycles/second with the internal accelerometer. This can find things like out of balance tires and driveshafts. Higher frequencies require an external accelerometer which is quite pricey ($750). The app can do both so for the paltry price of $5 (shameless plug for my app) you can give use it for lower frequencies. If the vibration actually makes an audible buzz the app can also sample the microphone and show you the frequencies it hears. If you are going try this PLEASE have a copilot operate the app. We don’t want to lose any Subi owners!
 

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2018 Outback 2.5 Limited w/ Eyesight - Magnetite Gray
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Discussion Starter · #13 ·
These problems are tough to find. The best way to do it is to measure the frequency of the vibration and then start computing what runs at that speed. At about 70 mph the tires rotate about 10 rotations per second. I do not know the rear axle ratio on the Outback but assume it is 3.9:1 which is typical of many cars. Then the driveshaft is rotating at about 39 revolutions per second. If the tranny is 1:1 at 70 then then engine is also running 39 revolutions per second. If you have a 3.6 there are three combustion’s per rotation for a firing rate of 117/sec, if it is a 4 cylinder then you have 78/second. Hopefully now you get the idea. So you need to measure the vibration frequency and knowing the characteristics of the car do some math and figure out what matches the vibration. Automakers do this stuff all of the time. Dealers typically are not smart enough to figure this out.

I happen to be familiar with this because I sell an iPhone app called Vibration which is used by some auto makers and tire makers to look for problems like this. The iPhone can measure up to 50 cycles/second with the internal accelerometer. This can find things like out of balance tires and driveshafts. Higher frequencies require an external accelerometer which is quite pricey ($750). The app can do both so for the paltry price of $5 (shameless plug for my app) you can give use it for lower frequencies. If the vibration actually makes an audible buzz the app can also sample the microphone and show you the frequencies it hears. If you are going try this PLEASE have a copilot operate the app. We don’t want to lose any Subi owners!
Thanks for the detail. My problem still exists and am very frustrated, much like others here, that the dealer/SOA refuses to acknowledge that a brand new car should not vibrate down the highway. I plan to purchase the app to do a little sleuthing. Is the correct app from Diffraction Limited Design in the Apple app store?
 

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2018 Outback Limited 2.5i and 2018 Audi A4
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Thanks for the detail. My problem still exists and am very frustrated, much like others here, that the dealer/SOA refuses to acknowledge that a brand new car should not vibrate down the highway. I plan to purchase the app to do a little sleuthing. Is the correct app from Diffraction Limited Design in the Apple app store?
That’s the one. Post here or send a pm if you have questions.
 

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2018 Outback 2.5 Limited w/ Eyesight - Magnetite Gray
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Discussion Starter · #15 ·
That’s the one. Post here or send a pm if you have questions.
Thanks - really nice utility! Purchased the app and will gather some data for the next few days.

Two quick questions for you.

1. Any tips for where and how should the phone be positioned during the sampling? No phone mount; cup holder, dashboard, seat?

2. Based on my very quick dive, I've configured a 5 second delay with a 20 second sample length. Any other 'crash course' settings we should pay attention to? I think I understand the concept but it will be helpful to examine the raw data and play around with it.

I will post data/results and certainly appreciate your willingness to help explore this.
 

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2018 Outback Limited 2.5i and 2018 Audi A4
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Thanks - really nice utility! Purchased the app and will gather some data for the next few days.

Two quick questions for you.

1. Any tips for where and how should the phone be positioned during the sampling? No phone mount; cup holder, dashboard, seat?

2. Based on my very quick dive, I've configured a 5 second delay with a 20 second sample length. Any other 'crash course' settings we should pay attention to? I think I understand the concept but it will be helpful to examine the raw data and play around with it.

I will post data/results and certainly appreciate your willingness to help explore this.
1. I recommend that the phone be placed on something solid. Lay it on the center console spanning the cup holders or on the dash above the display screen. You want a good solid connection to the car so avoid squishy soft phone cases.

2. Make sure you select Data Source -> Internal Accelerometer and then go to Settings -> Data Acquisition settings and slide the sample rate slider all the way to the right. In Settings -> Time Series Display Settings turn on Auto Scale and Subtract Mean. In Settings -> Frequency Display Settings make sure all axes are turned on. I also like to turn on Log scales for both axes, it makes it easier to see peaks throughout the frequency range.

Once you acquire the data, switch to the frequency tab and then you can touch the screen and move the cursor to examine each frequency peak. A pop up display with show you the amplitude and frequency. If you want to examine more closely you can double tap on a peak and the screen will zoom in to the point where you tapped. To zoom back out, double tap again.

Good Luck!
 

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2018 Outback 2.5 Limited w/ Eyesight - Magnetite Gray
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Discussion Starter · #18 ·
1. I recommend that the phone be placed on something solid. Lay it on the center console spanning the cup holders or on the dash above the display screen. You want a good solid connection to the car so avoid squishy soft phone cases.

2. Make sure you select Data Source -> Internal Accelerometer and then go to Settings -> Data Acquisition settings and slide the sample rate slider all the way to the right. In Settings -> Time Series Display Settings turn on Auto Scale and Subtract Mean. In Settings -> Frequency Display Settings make sure all axes are turned on. I also like to turn on Log scales for both axes, it makes it easier to see peaks throughout the frequency range.

Once you acquire the data, switch to the frequency tab and then you can touch the screen and move the cursor to examine each frequency peak. A pop up display with show you the amplitude and frequency. If you want to examine more closely you can double tap on a peak and the screen will zoom in to the point where you tapped. To zoom back out, double tap again.

Good Luck!
Wow, really neat stuff here. Over the last few weeks I have been playing with the app to collect some data... now I just need to make sense of it.

I've put together a spreadsheet that includes some calculations based on oscillations/second, tire size, speed, etc. I also pulled averages from the same routes to try and smooth out the data, but I still can't make heads or tails of it. My math could have serious flaws, or the logic in general. I'm really hoping to narrow it down to some group of components.

If anyone has a few minutes to take a look I would really appreciate it!

bardmany2k.mywebcommunity.org/VibrationData.xlsx

On a side note, I've tried 3 of the CKE interts. Absolutely great products and customer service! I think my issue is beyond what they are designed for though, since there was little difference in my case.
 
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