Resonance at around 70 MPH?

[rjgough95]

Originally Posted by bjreynolds202

If you have stock exhaust, and add Whiteline bushing inserts to the trans, differential and subframe, this noise will increase quite noticeably as a high pitch whistle right around 69-73mph for me. I never noticed it before the bushing inserts. No whistle at 35mph, but slight vibration from the bushings. Definitely coming from differential though. speed dependent and not throttle input. Just my personal experience.

Interesting ill have to keep that in mind with them and see if that helps figure anything out.

[menikmati]

The Whiteline differential inserts (KDT925) cause a noticeable amount of noise at that speed range. The sound is supposedly lessened if you choose not to install the front inserts.

[rjgough95]

Well i just got a call from Subaru shop and they start off by saying they took it out when we agreed to do a drive with a mechanic Saturday morning at 8am so i have to leave my house and have my family member drive hour just to get there. Both mechanics could not make the noise and she goes on to say that both took the car to an average speed could not hear any suspension noise. First off average speed doesn't sound like 68-72MPH. Second when the hell did this become suspension related, multiple times i have said differential. Last time i even gave them a digital sound recording on file you could hear it. Ive been more then helpful with this situation with them.

[rjgough95]

Well looking through all the pages i see that the rear differential was actually not a fix for this issue that was stated at the beginning of this. Stated later on in a post that the new differential did not solve the issue.

[rjgough95]

Just got a call from the service rep and he took out my car for a long drive and had it in between 68-75 MPH and could not hear the noise. Since i just found out the diff replacement did not fix it i am just done trying to fix it at the moment.

[jcblown13]

I use this car as my daily driver for almost 3 years now since new. Mostly highway and that's where I hear this high pitched whine noise. I have the manual transmission and if I push in the clutch or shift to neutral while doing about 70 the sound instantly stops. It seems to have gotten worse with age (car has 50k on it now).

[BRZnut]

I have had this rubble around 70 MPH since day one. Now at 26K miles, it is still there. No change. No better/ no worse. It seems to be a "normal" characteristic of this car, sort of like the crickets, IMO.

[zmz0305]

Originally Posted by jcblown13

I use this car as my daily driver for almost 3 years now since new. Mostly highway and that's where I hear this high pitched whine noise. I have the manual transmission and if I push in the clutch or shift to neutral while doing about 70 the sound instantly stops. It seems to have gotten worse with age (car has 50k on it now).

Hi, I posted this whistle noise here: http://www.ft86club.com/forums/showthread.php?t=105386

Is this the whine noise you were mentioning? I was having it on highway too but now I am having it while idle.

[Shane0mac]

So does everyone get this sound? Mine starts around low 60's and continues through the high 70's... its getting rather annoying. Any fixes yet?

[Hueco]

Hi guys, I'm new to the group but I've been hovering around the forums for some time now. It could be that my experience is not relevant but this thread is the closest I could find that matched my issue.

I'm not sure I notice a increase at 70, only a whine under load. I do notice an increase in vibration/resonance at 3000-3200 RPM when accelerating or just holding at 3K RPM. I first noticed the increased vibration after installing the whiteline KDT925 kit, figured the added stiffness was amplifying an existing resonance already.

This past weekend I decided to pull out the differential bushings since all the added noises that came with them made me feel uneasy, to my surprise I still noticed the higher vibration at 3k RPM (although much quieter), I don't ever remember noticing it before I added the bushings. It could be that I'm much more aware of it now, I would really like to know if its normal.

I am wondering if its possible to have re-mounted the differential in a way that now causes excess vibration. Anyone know if remounting the three bolts requires careful alignment, or is it OK as long as the bolts go in? Could it require a wheel alignment?

I've got to go get an oil leak and a damaged bumper fixed so I will probably have the differential looked at while its there.