Unknown drivetrain noise

[kmartind]

I've noticed a kind of faint growling noise that appears to come from below the center console. At higher speeds it becomes more of a whine, just slightly metallic sounding, but not pure grinding-metal-on-metal. Car is a '99 GSX with only 36K on it.

It changes pitch with vehicle speed and does NOT change with engine speed but may get slightly louder when accellerating or decelerating in gear. However, it seems to occur both in and out of (any) gear, with and without the clutch engaged.

Things I've done so far:
- Checked out the brakes and changed the pads and rotors.
- Changed fluids in tranny, transfer case, and rear diff (all three were basically full, and the magnets had picked up some metallic gunk, but nothing larger than a a little bit of fine powder).
- The drive shaft carrier bearings don't look particulary bad (from the outside) but I haven't pulled them off yet to look at the bushings.

None of the above made any difference. The noise has gone on for months (perhaps a year or more) but the car has been parked a lot. I took it out on the freeway again recently and when I came back I noticed the noise was much louder and more noticable than before so I'm no longer comfortable driving it and it's going to stay in the garage until I figure this out. I'd like somewhere to start though, before I start pulling things apart and/or replacing them just because they "might" be it.

Here's a vid of what the noise sounds like now(1.3MB):
The Noise

Now in the garage it sounds almost like a tranny noise to me, but on the road I'm pretty sure it happens in any gear, or out of gear, and with or without the clutch pressed. I just couldn't really tell where the noise is coming from, it seems to resonate through the body a bit.

Any ideas other than the above?

 

[GalantGst]

hmm sicne ur on the lift turn off the car and leave it in nuetral and spin the wheels by hand maybe its the wheel bearings.

 

[kmartind]

I couldn't really hear anything when spinning by hand, but then again I can't spin a wheel all that fast by hand. It seems to start around 15-20MPH or faster.

 

[GalantGst]

hmm cna u have some one else drive the car i dint see its gsx maybe its the t case?

 

[krazywhitboy]

STOP DRIVING IT!!! It sounds like either the transfer case or the rear end. Have you had the t-case recall done? check the fluid in the t-case and rear diff...is there any fluid leaking from the transfer case area? be very careful, if either the t-case or rear end lock up, you will have major problems, the wheels will lock up and you will go into a skid....not good....

 

[kmartind]

STOP DRIVING IT!!! It sounds like either the transfer case or the rear end. Have you had the t-case recall done? check the fluid in the t-case and rear diff...is there any fluid leaking from the transfer case area? be very careful, if either the t-case or rear end lock up, you will have major problems, the wheels will lock up and you will go into a skid....not good....

Yes I've stopped driving it, but it's a '99 so no transfer case recall. Only the lower ball joint recall applied to the '99s and that's been done (but wouldn't have anything do do with the noise of course).

 

[krazywhitboy]

oh duh i didn't realize it was a 99....well i'm still almost positive that its either the t-case or rear end, i've heard that noise on my mustang when the rear end was going out and on my 300z when the rear started to go....