About a couple of days ago, i noticed that the usual high pitched very slight noise that I always got from the rear when de-accelerating doing about 3 to 4,000 RPMs just got a little louder.

has anybody experienced this?

I know that you also get the decel noise from the clutch but thats not it as I replaced my whole clutch assembly so I know its coming from the rear

 

Yeah I hear that to on my MY03. I can't firgure what's doing that. May be it's normal? Anyone else?

 

It could be the diff. going out, might want to check that.

 

Mine does not do that. You mean you decelerate from only 3 to 4,000 rpm's and you hear a high piched whine? That does not sound good. Mine does not make any noise at all. What year is your car? is it under warrenty still? Just be careful because there is a remote possibility that the diff could lock up and cause an accident.

If this were a normal characteristic of this car, wouldn't mine make this sound to??

 

[QUOTE]Originally posted by RACER
Mine does not do that.

 

Have you replaced your rear diff fluid yet? If you haven't done it recently, that wouldn't hurt. Besides, at 30,000 miles with aggressive driving, you're overdue.

If you did have it changed, is it possible that someone put the wrong gear oil in? Some brands of gear oil are not intended for our car, and require the addition of a friction modifier to get the limited slip to work properly. I wouldn't expect a problem with a straight-line deceleration, but then again, I'm not an expert on limited slip differentials.

Also, check for leaks around your differential. That high-pitched whine is likely the sound of the gears meshing. Lack of lubrication could cause it to get louder.

If you do get your differential fluid changed, you might want to read some of Road Rage's suggestions on rear diff fluid. A slightly heavier lube oil might be best for you.

I should mention that the whine will be greater when decelerating in lower gears. The faster the deceleration, the more force on the gears. And since the back side of the bevels in the gears don't mate up as precisely as the front of the bevels (which are used to drive the car forward), the differential whine will be louder when decelerating (or accelerating in reverse).

 

[QUOTE]Originally posted by slalom44
Have you replaced your rear diff fluid yet?

 

Gear oil does a number of things, and one of them is damp gear noise. Honda recommends a straight 90 weight, and since you have RedLine in it, my guess is that you used their 75w90, which will be thinner at most temps, and has less gear noise cancelling effect.

When i change my diff oil, I am doing a 50:50 mix of 75w90 and 85w140, which will yield a lube with plenty of cold weather flow, and yet is closer to Honda's spec. Oh, the mix yields an 80w115, which is marginally thicker at high temps, so it should offer better wear protection and absorb shocks well.

Of course, you could just have wear, and it manifests itself by a whine at certain speeds. My Outback has a bunch of diffs, and has a whine at 45-60 mph - I bought it used, so it may have been there at the start, but when I added my "cocktail", it got quieter, and what came out looked good for the miles it had on it.

 

I've heard the same noise...not too loud, just something that did not seem right. Slight high pitched whine. It only seems to occur after long periods of driving. I have a MY04 with less than 6000 miles so I don't think diff fluid is the culprit.

 

Then I suspect it is normal characteristic - as I said, my Outback has its noise points. Mechanisms, esp something like the ring and pinion, can have resonant frequencies, so this may be what is going on here.

I have 300 miles on my car, and hear nothing Out back.