Didn't notice until recently since I usually enjoy the stereo, but at any speed, easier to do it at low speeds, ~5-15mph, if going through a bumpy road where the car sways, there is a clunking sound coming from the rear. Sounds like a broken sway bar, but I checked and it's fine. Something is loose, just don't know where. I'm going to check the spare and jack tomorrow when I have time. Would the exhaust swing so much as to hit something underneath? Anyone else ever hear this? Should I take it to my dealer tech? Could some of you guys try this out in your Z's? Shut off the stereo, roll windows up (it's better since it cuts outside noise off), and find a lumpy road at ~10mph. Thanks.


Oh and for the reference, I do not have anything in the hatch that's banging around, nor in the glove. You can definately tell it's coming from outside the cabin towards the rear of the car. Sounds just like a sway bar hitting the link, except it's not.

 

I had the same problem and found that it was the passenger side seatbelt making the noise when it's not engaged.

 

I just started noticing that on mine., I have been assuming its the forward mount (of the 3 on the muffler) since I had a custom setup that didnt use it, then when I put the borla on, I didn't have the hardware to use that mount.

I since have gotten the hardware am going to install it soon, but since you have the problem too, I doubt that is what it is.

Does it sound like its from the right rear?

I;ve heard some driveshafts/axles haven't been properly torqued, but I would expect those noises when you put stress on the drivetrain and not from bumps. Keep me posted if you figure it out, and I'll do the same.

 

It could be that the spare is loose. Also the cover over the spare can move on big bumps.

 

Stonesfan, I will make sure both seatbelts are secured with the hook, but it clearly sounds like it's coming from the outside of the car.

2003z, hard to tell which side, but clearly from the rear of the vehicle. I'll try to determine which side tomorrow.

And will also check spare + jack tomorrow.

If I can't figure it out and have time, I'll take it to the tech for a test drive. Of course, I'm sure once the tech's in the car, it won't do it

If I figure this out, I'll be sure to post.

 

It does it on a roll in neutral (6-spd) over the bumps as well as in gear, so that should rule out the tranny/drive shafts. Imagine if it was, that would be a b*tch.

 

Yes please let us know if you find out what's causing it.

 

I had the problem with the loose axles and it doesn't sound like what you are having. Mine would make a clicking sound when shifting gears at low speeds, mostly in 1st, 2nd and sometimes 3rd, but I don't remember it happening over bumps. I would take it to the dealer and have them check it out under warranty, if it is a loose axle it is as simple as them tightening a few bolts to fix the problem.

 

recent 1 year motor trend test drive said they had metallic grinding noise from rear..their problem was rear brake backing plates were loose...fixed by dealer free...

 

mine definitely isn't the spare tire. Double checked everything secure in the back and it still does it.

 

Behold, found it!

Unbelievable as it may be, Stonesfan was right, it was merely the seatbelts flapping against the panels. What made it so hard to tell was the fact that if you take the belts by hand and start hitting the panel yourself hard, it clearly sounds in the cabin, but if you take the belt and just calmly hit the panel with it, the sound is muffled and reflected inside the plastic panel, not inside the cabin. This sounds like it's coming from the outside of the cabin, or the car. Not only did it fool me, it also fooled my fiancee.

Good luck to the rest of you with similar noises eminating from the rear. May the Z live on.



ps: for reference, I did remove everything from the rear (personal items) and glove box, found a nice "test" road in which the noise always came on, and drove with and without the seatbelts hooked. I also made sure bu unhooking just the driver's side and put my ear there as I went over the bumps as well as a good look at it. Sure enough, the belt was flapping against the body panel.

 

I'm so glad I was able to help you!
When I read the other responses I kinda felt like a "dumb" woman (when it comes to cars). Who knew? :-)

 

what about you 2003? My car does this as well, and I always thought it was something in the trunk area (or the spare). I checked both today and nothing. Getting a little concerned.

 

my 03 z had the same problem, basically a clunk sound, I brought it to the dealer and he told me that the rear linkage was not tight enough, do a search and you will a thread that also address the clunk sound problem. basically some z did not have the bolts tightened properly, i think 42 ft/lbs was proper spec...do a search for "clunk"
Its been 3 months since the bolt was properly tightned and yes the sound has completely disappeared now
good luck
PS
the sound would always occur when I would drive backwards about ten feet, stop and then drive forwards (clunk)

 

Yes, always good to drive on both good and bad roads with the windows both open and closed while having the radio off to "hear" the car every now and then. You'll be surprised what you might hear, might as well be while it's under warranty

 

haven't driven mine in awhile or looked at it yet.