Symptoms:

-Something in under my '96 sounds like either a rattle or a rock in a bucket with a rusty handle.
-It's most pronounced when I go over 'washboard' bumps, and when I take my foot off the gas... though neither of these guarantee that it will make the sound.
-After slowly driving over a large bump, I stopped and there was a delay before the 'rock' moved in the 'bucket'. It's like something had inertia, and was able to swing freely.
-After poking around under the car (and finding nothing amiss), it made the noise upon pulling out of my parking space.
-Sometimes the sqeaking is incessant, but then after going around a corner or a few bumps the squeak goes away for a few hundred feet.
-Sounds lounder when I open the windows and drive by fences, so it's quite audible from outside the car.


What I have checked:

-The exhaust: it's probably original, but nothing moves when I shake it by hand or nudge it by foot. Seems solid.
-The rear sway bar: supposedly caused a similar problem in the past... but just the rattle and clunk without the squeak. Great amounts of force won't make it budge, so I doubt that's it, but I could be mistaken.
-Panhard bar: seems solid, everything looks as it should be. Can't get it to budge.
-The heat shield. Although it's not in the rear of the car, I thought I'd check it anyway. Seems solid, with no sign of coming loose.
-Trailing arm suspension links look great, feel solid and show no signs of anything wrong.
-Rubber bushings etc. seem Ok, though shock absorber bushings look slightly cracked.


What I hope it's not, but kind of suspect:
-The drive shaft: seems like there might be slight play, but it's barely noticeable if anything.
-The axle/rear end: doesn't whine, but maybe something's loose inside that makes noise but doesn't otherwise effect driveability?
-Loose gas tank: though it feels solid
-The sway bar, simply because that caused problems before. Mechanic tightened it up for free, and the problem went away... but darn it, I can't get any movement out of the thing, and it looks well bolted.

The symptoms are getting progressively worse. I've been driving it with intermittent rattles for over 3K miles. I thought the problem would develop into something noticeable upon inspection of the undercarriage, but it hasn't... at least not to my eye.



Any thoughts and/or suggestions?

Thanks in advance!

 

most of the noise problems I have had have been eliminated by tightening the lower control arm bolts. I did have a similar noise and it turned out being the access panel at the rear of the left rear wheel well. It allows access to the fuel inlet and filtering system. The squeak sounds like a bushing however. Good luck finding it.

 

Thanks. On your advice, I checked it out, and it's not loose. The sound is mostly coming from the other side.

I hope the squeak is only a bushing. That I can live with. As for the other sounds, I hope nothing falls apart on me... because that's what it sounds like.

Will have the car on a lift this Monday, to get to the bottom of it. Based on advice in another thread, I'm thinking it may be a loose or broken tranny mount. There isn't a heavy clunk, but it may be heading in that direction.

 

Mystery solved. The driveshaft bracket was loose. Apparently it's a two-piece, different than on the Z28... so I didn't even think to check there. Now that it's tight, The squeak rattle and clunk are gone.