55-65 MPH Whine from rear.

[TheBigChill]

 I don't usually start posts based on sounds that I hear, but over the past 2 months I've taken note of a "whining" or "whirling" coming from what would seem to be the rear of my car.  It is only really audible at ~ 58-65 mph, primarily 60 mph dead-on.  Any faster than 65 and I don't hear it at all, and under ~55mph I don't hear it at all either.  If I accelerate to say ~70mph and put the car in neutral, and coast back down, it still makes the sound at ~60mph on deceleration, then is gone.  


 I know there is a TSB for the rear diff (harmonics dampening).  See below.

*

Countermeasure to Eliminate Noise from the Rear Differential Area

Service Bulletin #03-55-05
Pages: 2

Bulletin Description: A countermeasure has been made to address noise coming from the rear differential area. The noise may make a high frequency ýHooý (Harmonic) noise and is most noticeable with little to no throttle application (coasting or deceleration). The peak of the noise occurs at 63mph (100km/h). The noise may occur in any gear or engine speed; however it is most noticeable in 4th gear (4EAT equipped) or 5th gear (5MT equipped). Dynamic dampers were added to the rear differential member to eliminate the noise. If you encounter a customer complaint prior to the countermeasure, follow the procedure on page 2.

[/b]

 Like most things w/ car issues, this explanation isn't an exact match, but it's similar enough to take note.   I guess my other suspect would be a rear wheel bearing going bad....   I'll have to drop by RPI, and throw it on the lift to see if any wheels are shaking.    Have any of you guys had the rear diff issue, or a comparable issue that turned out to be either one of these potential problems ?  This car and it's fussy little fucking noises are / have been getting on my nerves A LOT.

[Photofixer]

print the shit out and goto subaru.. 

[TheBigChill]

  I'm trying to avoid silly Diagnostic fees and stuff like that right now, but might do that, Marty.  Just trying to see if others had similar experiences and what their solution was before I start paying out for this.  I must've been high buying a 1st year WRX, out of warranty...

[Photofixer]

Their was also a recall on the fuel injectors o rings.. but I don't think that applies to you.. since you already replaced yours.. HA

[TheBigChill]

Their was also a recall on the fuel injectors o rings.. but I don't think that applies to you.. since you already replaced yours.. HA

 Peter and I....  Thanks for rubbing it in, Marty, haha.

[Photofixer]

  

[gebby1029]

Have any of you guys had the rear diff issue, or a comparable issue that turned out to be either one of these potential problems?

Yes.

Your symptoms sound very similar to the ones I had.  Whining noise that got louder with speed (especially on highway), more pronounced at zero to very little throttle input.  What ended up happening with mine was that my bottom differential bolt had somehow come loose and drained out just about all fluid.  After discovering this, I did top off my fluid but the damage had already been done.

In short, sounds like a differential issue to me.

[TheBigChill]

Yes.

Your symptoms sound very similar to the ones I had.  Whining noise that got louder with speed (especially on highway), more pronounced at zero to very little throttle input.  What ended up happening with mine was that my bottom differential bolt had somehow come loose and drained out just about all fluid.  After discovering this, I did top off my fluid but the damage had already been done.

In short, sounds like a differential issue to me.

  I looked under the car today, and my drain plug is there, with no signs of leakage.  I'll open it tonight at RPI, and look around.  Drain plug should be caked with particulate if there IS a Diff problem I'd assume.

  I changed the rear diff fluid maybe 2-3 months ago, with the OEM LSD Oil, LS-90 (Yes, I know I don't need it, but oh well).  Using that fluid should not cause any issues over using Extra-S or comparable, correct ?

  The thing about my problem is:  It only makes the noise (that I can hear...) from like 58-63 mph.  Above or below, it's quiet.  I'd think that if something was damaged, it wouldn't be so speed dependent and would make noise through a wider variety of conditions.   The TSB above, doesn't indicate that things are damaged, merely that there is noise and measures would be taken to simply dampen the noise.  Obviously noise IS vibration, but.... IDK  This sucks, haha.

[Kavik]

i agree, take it in to the dealer along with a print out of the tsb.  They'll see if you need that specific issue fixed, if not they might just tell you if they noticed any other problems while they were checking on that 

shouldn't be a charge if there's a tsb about the issue, right? or does that only apply to full on recalls?

[FastfreddyRs]

shouldn't be a charge if there's a tsb about the issue, right? or does that only apply to full on recalls?

you will get charged for a TSB if your vehicle is out of warranty. Recalls are free with unlimited mileage.

All a TSB is used for is to help tech diag a specific concern that has been brought to the attention of SOA so they share the findings within the company.

[TheBigChill]

you will get charged for a TSB if your vehicle is out of warranty. Recalls are free with unlimited mileage.

All a TSB is used for is to help tech diag a specific concern that has been brought to the attention of SOA so they share the findings within the company.

 Super, thanks Fred.   Anywho, I think that TSB is geared (no pun intended) towards the '04-'05 WRX...  Not sure though..

[TheBigChill]

 To supplement my description : 

 http://forums.nasioc.com/forums/showthread.php?p=8799794#post8799794

 http://forums.nasioc.com/forums/showthread.php?t=708096&highlight=differential+whine

                                             

[SideshowBob]

I would just tell your GF/Wife to shut it.

[TheBigChill]

 Ha !  Been there, done that.  Still, the whine remains.  



 Well, I'm sick of my own thread already.    It's gotta be the "Hooo" noise from the rear diff that's in that TSB.  After driving home today, the noise is really only there at 60mph +/- 2mph.  It's limited to such a tight MPH range, I doubt it could be a wheel bearing. 

[spoolordie]

Drive it till it breaks

[TheBigChill]

   I can't do that.  I need to figure this out and fix it.

[darksideSTI]

Has the noise been there for awhile or only since the fluid change? I would agree w/ getting the TSB looked @ and giving that a shot. Tire noises and wheel bearings are usually constant and speed dependent. Only within the few MPH points to TSB or possible fluid level/ type.

[TheBigChill]

 I'll call a dealer today.  Essentially, the "fix" for this "problem" is:  They bolt some weights possibly with rubber as part of the weighted assembly, to the Diff cross-member on each side to dampen the vibration / noise.  When that's the type of "fix" a dealer does, it tells me that it's not likely a impending mechanical failure, but rather to fix an annoyance. 

 What bothers me is that I never noticed this before and I'm pretty anal about my cars.  It's possible I missed it, but not likely.  Though, I don't recall the noise appearing right after the Diff fluid change, because that was several months ago and this noise was just realized recently.   I'll look at my diff fluid and magnetic plug at RPI tomorrow, but I highly doubt there is any issue with the fluid level, as that's a no brainer.  Like I said, I used the Subaru LS-90 Diff Oil, granted it's for STI LSDs I'm still confident that it wouldn't cause any issues, rather it's simply overkill for my style of diff.

[darksideSTI]

difference between LSD fluid and normal is usually just an addative. so maybe it might be like not using LSD fluid in an LSD having an inverse reaction. but that could be a stretch. talking to a fellow technician say to double check u-joints if there are any

[TheBigChill]

difference between LSD fluid and normal is usually just an addative. so maybe it might be like not using LSD fluid in an LSD having an inverse reaction. but that could be a stretch. talking to a fellow technician say to double check u-joints if there are any

 Exactly, it's an additive.  I'll look around tonight.

[RedRoof2]

Just a thought:  Put your front tires to a few or more PSI higher than your rear tires, then go drive it again.  See what happens to the noise.

[TheBigChill]

 I'll try it.  It's still occurring, and still from like 59-61 light throttle.  "Hoooo"   I feel like Bub Rub

[RedRoof2]

I'll try it.  It's still occurring, and still from like 59-61 light throttle.  "Hoooo"   I feel like Bub Rub

Get em while they're hot.

[TheBigChill]

 ^  Oh my lord.....amazing.   How have I gone on living not seeing that ?


Fucking sound is still there.  I'm going to temporarily install some weights down there, and see if it goes away / changes anything.

[RedRoof2]

Well it's obviously a sort of resonance.  When you load up the drivetrain, it goes away, because the load acts as a damping force.  Have you been able to figure out where exactly it's coming from?  If it's center diff whine, try a higher viscosity gear oil, like Redline Shockproof.   If you can crawl under it, see if there's play in the carrier bearing.  If you have a lightweight flywheel on board, that will also make this noise due to the fact most any aftermarket flywheel is NOT a dual-mass design, like the OEM unit.  Perhaps your flywheel itself is the cause and the sliders onboard the unit are not allowing the secondary ring to slide?

Does it also happen on light decel?  If you load up the rear diff in the opposite direction under light load, lemme know if the noise can be duplicated.

Also try ruling out stuff under the hood.  Cycle the A/C on and off, see if it changes.  Check to ensure you're not hearing noise from an idler pulley or such, that may be going bad.