I get this clunking noise when going over railway tracks or drops in pavement height (e.g. recessed manhole covers). The previous owner also complained about this to the dealer who checked it out and the response then (2005) was: All secure. No abnormal noises heard on several tests over track crossing.
Is the word ABNORMAl significant here? Does that mean that the noise (like something loose thumping in the trunk) is normal?

 

I think it is the trunk proper, I have checked for a loose jack, maybe my spare was loose, nothing

 

Where is the noise coming from, the front or the back?

 

The noise is coming from the back. Had the car up on a lift today for an inspection. Told the mechanic about the noise and he probed and prodded everything and found nothing. Everything is tight and solid. Anyone else experience this? Should I just accept it as a normal thing for the car?

 

Video please...or more description. I do not have this noise from the rear of my 2002 SC430

do you have something loose in the spare tire storage area or are the tools/jack loose?

 

I checked everything in the trunk and all is secure. I am going to remove everything (no spare in the trunk) and see if it makes a difference. The sound is like that though - something heavy bouncing in the trunk. Just one clunk though. Interestingly enough, it does not make the noise going over expansion joints on bridges. It seems to only be when there is a drop.

 

The black tool tray could be bouncing. It sits on four pins and those pins should have black plastic caps on them. Do they?
if not that could be your noise.

also, does it make the noise with the top up or down?

 

I will check the four pins. Did not notice when I looked at it.

It makes the noise whether the top is up or down.

I'm liking the idea of this forum!

 

If this tray bounces, it will make noise.
one of the pins is on the right side under the tire lug wrench,
then left side under small black bag.
the other two can be seen in the pic, they are in the spare tire storage well, far left and right sides.

 

Yeah, check those four pins that hold down your jack tray. If the tray has ever been removed, chances are the threads on those caps are stripped and they are not holding the tray in place. Might also want to check your jack to make certain that it is wound "out" far enough to keep the jack in place. I've had my trunk area apart several times and there is nothing under the trunk interior that would be making a large sound.

 

Thanks. I'll definitely check that out tomorrow!!

 

Well, I took all tools out of the trunk and made sure the four plastic nuts were secure. Still makes noise. I am thinking it is something with the suspension. The roads are rough around here so I hear it a lot.
and for the other noise. If I put the brakes on firmly, when the car comes to a stop and settles back (pushing you into the seat), there is a noise. Again from underneath somewhere. If I am lucky, maybe caused by the same thing.

 

has anyone modified the GPS, stereo or anything that is stored in the back of the car?
the GPS and ML amplifier are in the trunk and if someone worked on them, they could have forgotten to bolt them down...I am only saying this because you said the outside has been gone over very well.
Trunk area:

 

Be sure to look at post #415 in this thread.
https://www.clublexus.com/forums/sc4...-today-11.html

 

Thank you for that reference Bgw70. I'll have to check that out.