Resonance at around 70 MPH?

[Stu baru]

So I picked up my car from the detailer after work yesterday and noticed that the pattern of occurrence of this has changed. The 50 mph zone is less dramatic, and a bit more intermittent. This is interesting, in that the detailer removed all the wheels to clean and Opti-Guard them. I've not contacted him yet to see if they went back on in the exact same locations or not, but this might imply tires, alignment, and/or balance as a source. I need to do some evaluative driving to see what the new sound pattern is. She goes in for her complimentary first oil change Saturday and I've already alerted the service department that I want to demonstrate this and the DI chirp. More as it becomes known...

[alan329]

You should ask you dealer to look this up.

Service Bulletin # 05-50-10R
Noise, Vibration and Harshness (NVH) at Highway Speeds Caused by a Tire Imbalance or Excessive Radial Force (revised)

[sdshores08]

Any news on this? I've noticed this noise at 70 since the day I picked it up two months ago. I also have the noise at 35.

[Subie]

Originally Posted by sdshores08

Any news on this? I've noticed this noise at 70 since the day I picked it up two months ago. I also have the noise at 35.

Please call Subaru at 1-800-SUBARU3 (1-800-782-2783) and reference case number 1-205-1692411. At least as of several days ago, no one that I had privately asked to call Subaru had actually done so. I am meeting with the district rep. on the 22nd and want to have all of my ducks in a row before then.

[FirestormFRS]

Yeah I got that same droning humming annoying sound dead @ 70mph in my FR-S. I just drive faster and it goes away

[Subie]

Originally Posted by FirestormFRS

Yeah I got that same droning humming annoying sound dead @ 70mph in my FR-S. I just drive faster and it goes away

Call Subaru and reference my case if you want an actual resolution. This issue appears to be more widespread than I initially thought.

[sdshores08]

I called them, but I couldn't open up a case or anything since mine's a Scion. The lady told me that she would make a note in your case that I called about having the same issue.

[Subie]

Originally Posted by sdshores08

I called them, but I couldn't open up a case or anything since mine's a Scion. The lady told me that she would make a note in your case that I called about having the same issue.

I appreciate you calling!

That's what I hoped she would do; I'm hopeful that they'll expend the effort to pinpoint the noise so that either a TSB will come out or at the very least it will be easier for others to get a resolution down the line. At this point it's up to you what you want to do about it; you could either go to your dealer and try to have it diagnosed or wait to see what the outcome of my visit is, first. Of course I'd be willing to call Scion for you should you open a case in order to return the favor.

[Silverpike]

God I can't believe there are 3 pages on this and nobody got the answer yet:

IT'S THE DIFFERENTIAL

I guarantee this is the answer. How do I know? My Subaru WRX has the exact sound you guys are describing. The reason comes from a firmly mounted rear subframe. The diff has a resonance right at about 60mph for me, and it got 10x louder when I installed subframe bushings. The resonance is anywhere in the 60-70mph range for all Subarus (newer subarus have slightly higher resonance points). It sounds like a loud, resonating pitch that fills the whole cabin of the car. The cabin acts like an amplifier unfortunately.

Unfortunately for me, it's very very loud. Nothing I can do, since I'm not pulling the bushings back out.

The way to mitigate this is twofold:
1. Buy high quality gear oil for the diff.
2. Add audio damping material to the car, around the rear subframe and the lower cabin.

I doubt anyone here will get a resolution from Subaru. This is not something easily fixed at the source.

[sdshores08]

Thanks! I'll let you know if I decide to call Scion. I haven't been driving on the freeway lately, but it'll probably aggravate me again the next time I do. I hope something comes from your case, please keep us updated.

[Silverpike]

Sorry I should add one more thing:

You can tell if it's the diff if the noise changes pitch and loudness depending on how hard you are on the gas. Both on acceleration and deceleration, the noise is loudest for me. Steady state cruising the noise is soft. All of this is inside the 60-70mph window, so if you test make sure to keep it in this range.

[Subie]

Originally Posted by Silverpike

God I can't believe there are 3 pages on this and nobody got the answer yet:

IT'S THE DIFFERENTIAL

I guarantee this is the answer. How do I know? My Subaru WRX has the exact sound you guys are describing. The reason comes from a firmly mounted rear subframe. The diff has a resonance right at about 60mph for me, and it got 10x louder when I installed subframe bushings. The resonance is anywhere in the 60-70mph range for all Subarus (newer subarus have slightly higher resonance points). It sounds like a loud, resonating pitch that fills the whole cabin of the car. The cabin acts like an amplifier unfortunately.

Unfortunately for me, it's very very loud. Nothing I can do, since I'm not pulling the bushings back out.

The way to mitigate this is twofold:
1. Buy high quality gear oil for the diff.
2. Add audio damping material to the car, around the rear subframe and the lower cabin.

I doubt anyone here will get a resolution from Subaru. This is not something easily fixed at the source.

I'm pretty certain it's the differential but I won't say it is the differential until the car's been checked out and the noise pinpointed by an experienced mechanic; that will hopefully take place in under a week's time. There ought to be something that can be done to remedy or mitigate the noise on Subaru's part; not everyone is reporting this issue which makes me hopeful that not every car suffers from this issue. I know for a fact the car I test drove way back when did not make this noise.

Originally Posted by sdshores08

Thanks! I'll let you know if I decide to call Scion. I haven't been driving on the freeway lately, but it'll probably aggravate me again the next time I do. I hope something comes from your case, please keep us updated.

Will do.

Originally Posted by Silverpike

Sorry I should add one more thing:

You can tell if it's the diff if the noise changes pitch and loudness depending on how hard you are on the gas. Both on acceleration and deceleration, the noise is loudest for me. Steady state cruising the noise is soft. All of this is inside the 60-70mph window, so if you test make sure to keep it in this range.

It's much more speed dependent than anything else. I'll experiment, possibly tomorrow, with different loads to see if the noise changes: I don't believe it does. There's a load-dependent whine from the transmission but it's not bothersome like this noise is since it 's ever-present when I'm in the speed range. The presumed differential noise is just slightly there outside of the small speed window, but it's very gaussian in that the intensity rapidly increases as I approach 70 MPH and then tapers off again.

[Subie]

Originally Posted by Silverpike

Sorry I should add one more thing:

You can tell if it's the diff if the noise changes pitch and loudness depending on how hard you are on the gas. Both on acceleration and deceleration, the noise is loudest for me. Steady state cruising the noise is soft. All of this is inside the 60-70mph window, so if you test make sure to keep it in this range.

I thought I'd follow up: it's seemingly not load-dependent, only speed dependent.

The car is at the dealer. I rode with the district rep. earlier in the day and duplicated all of my concerns. They are:

Resonance at 35 MPH & 67-73 MPH, centered around 70 MPH (thread topic)
Rattle from the trunk area
Rattle from the shifter/climate control area
Rattle from the headliner above the driver's left ear
A/C tweet
Passenger auto window down flakiness

The rep. seemed very receptive so hopefully everything will be taken care of. They're aiming to fix the rattles now, and research the driveline noise and A/C noise so that they can see what can be done about them. The rep. said he had a theory about the driveline noise so hopefully he can pinpoint the culprit and implement a fix.

[carbonBLUE]

Originally Posted by Draco-REX

There's a slight resonance I hear, but usually only if I have the rear seat down. The stock tires are pretty noisy for a "touring" tire. I think it's due to the tire's "low rolling resistance" nature.

Remember, this car has MUCH less sound deadening than most any other car you'd buy these days. It keeps the weight down as well as cutting a bit of cost. But the trade off is increased noise from the drivetrain and road.

i personally like that you can hear everything, adds to the cars raw driving experience!!! yes the noise is normal, change the tires and itll go away, or if you get better tires it may get louder because of more grip lol