I have this loud, humming....drone type of thing....but its kinda high pitched. I think its coming from the rearend....but it kinda seems to be coming right underneath the center console....cant really tell. Only happens above about 20mph.....and its pretty continuous....does not change according to speed or rpm or anything like that.......one weird thing though is that if i just barely rest my foot on the gas pedal.....and the rpms stay right at either 1500 rpm or 2000 rpm (depending on how fast im going) the sound COMPLETELY goes away.........its like heavenly bliss....but as soon as I take my foot off the gas the noise comes back again. Heres another weird part.....if I keep the rpm at either 1500 or 2000 rpm.........the sound will stop...but then I'll ride the brakes until I come go to about 10 mph...and the entire time the sound is not heard at all.....after i get under 10mph I can let off the gas and i'll stop fine....but if I ever let off the gas while im on the brake...the sound comes back again. Any ideas what could be wrong? When I redo the back brakes Im gonna change out the wheel bearings and check out the gears....but Im wondering if It could be the tranny or something.

Heres another weird thing. I was taking a friend home, and drove in his parking garage....as soon as I got on one of the ramps....I started hearing this really bad rattling sound....like someone shaking marbles in a can....I would turn the car off...then back on...and I could hear it again.....but as soon as I got back on the first level of the parking garage...it was gone....I was thinking maybe I hit my cat on the ramp....but why would it completely go away after I got back on the first level? Seriously....as SOON as I drove down the ramp it was gone. I think my car is falling apart.

Na, your car isn't falling apart, but your rear end is shot!

That sound you are hearing is the rear gears "whinning". Either you have been running the car with not enough gear oil in the differential, you blew the pinion seal and lost all the oil, or your gears are just plain dead.

Down to the point. You are going to need to replace all the bearings and the gear set - now will be a good time to swap gears and get a posi unit if you didn't have one already. The parts will be around $300, and the labor for having it rebuilt professionally will be around another $300... don't quote me on that, these are ballpark figures and are assuming you will be using quality parts. Might as well have them check your pinion angle while you are at it.

you might want to pull the rear cover and take a look around, inspect bearings and such. the noise could also be from a few other sources, like the tires or a bad u joint. never know till you look.

Actually, it's probably NOT the gears. They're pretty tough. It's more likely the pinion bearings need to be replaced.

Sounds to me like your rear U-joint is about to fall apart.

Get under the car and see if you can move the drive shaft around in the U-joint.

Ujoints are only a few months old. I just got a rear from a 96 Z off ebay so I'll just deal with the noise until I get that one in.

And that gurantees that they're good .....?

What it they weren't greased when they were installed? What if they were installed wrong?

Check them before assuming they're actually OK. Besides, who knows, while you're under there looking at stuf, you might see what the problem is, even if it isn't the U-joints.

Take a look, but the same thing happened to me in September. Changed the pinion seal, thinking it was a slow leak, and was dead within the week (think incorrect bearing pre-load).