Highway speeds - slight whine off gas or steady

[havand]

So, this is a minor issue, but one that I keep noticing. At highway speeds (55+), there is a noise that comes and goes. It sounds kind of like whine/growl. It is coming from the engine and the weird part is I only hear it at constant speed/slowing. If I am traveling at a constant speed, I can tape the gas it it goes away momentarily, until the car speed stabilizes, then i hear it again. If I accelerate, then let off, the moment the car goes from transitions from speeding up to slowing down, it comes back. I am thinking it is either a pulley or timing chain tension? Not really sure. Anyone else experience this. It isn't loud, but I do hear it every time.

[328ijunkie]

Diff.

[Jalves619]

Diff

[lbreevesii]

What are you guys talking about? he clearly needs a new muffler bearing. I recommend this one.

http://kalecoauto.com/index.php?main_page=product_info&products_id=10

seriously though, thats classic diff noise.

[cabriodster87]

http://kalecoauto.com/index.php?main_page=product_info&products_id=10

Want flux capacitor.

[giantkeeper]

Diff.

Diff

:nice:

[lolcantturn]

Diff.

[havand]

I understand the diff comments.... I have diff whine in my e36. This has too much depth and 'growl' to be it. It seems to be coming from the engine compartment. Maybe I'll try to catch it on video. It is pretty inaudible though....highway noise will probably drown it out.


EDIT: To be fair, my diff is not in the best shape. It has too much backlash and needs to be rebuilt. I think the pinion could be radjusted... I just haven't decided to tackle it yet.

[dirtysix]

Gbox input shaft bearing.





or diff

[ACHTUNG]

Diff

[havand]

Well... Since it seems to be unanimous diff.... Anybody got a good 2.93lsd they wanna sell me on the cheap? Or give me a hand adjusting the pinion depth.

[blackhawkimpact]

Yes, diff I have the same howl. Haven't had the time to replace it with the 3.73LSD I bought though.

[ButtJuice]

Replace fluid?

[jrdeamicis]

The vanos can actually be a very noisy device as it transitions between ON and OFF, because the excess oil pressure is vented through the front of the vanos unit.

I would start with some fresh good oil and filter.
Also check to make sure you have the updated timing chain tensioner.
Chains rarely break as long as you maintain the guides and make sure you have a good tensioner. (M42 is the problem child of this)
Dying lifters can also be very noisy. They create a strange strange noise.


Seriously though, you should change your diff fluid. More for the fact that I bet half the guys on here haven't even checked their fluid.

[havand]

Not the diff.

I played with it driving home tonight. Engine speed dependent. Doesn't do it below ~2000rpm. Does it like crazy at ~2500-3000rpm. I can cruise at 45 or 50 in 5th... no noise. Downshift to 4th to get the rpms up in the range and BAM. Does it.

Maybe a vibration because of a lightweight flywheel?