Chasing down a vibration noise

[Elkins45]

Next to an intermittent electrical fault there’s nothing more annoying than trying to find a rattle. My 09 Scion has started making a really annoying buzzing rattle from somewhere in the rear. I unloaded everything in the back including the jack, spare and other assorted gear but that wasn’t it. Arrgghhh! My first thought was maybe the back hatch glass is loose but I believe that it is glued in. It seems to be a harmonic because hitting bumps doesn’t cause it but it’s somehow influenced by holding the brakes at a stoplight. Exhaust bracket maybe?

I’m hoping something will be obvious when I crawl under it tomorrow. I was planning on putting it up for sale soon but who would buy it when it’s making noises?

 

[Pterostylis]

Similar sounding thing happened to a relatives car that I service, I tracked it down to something in the rear muffler. Probably a collapsed baffle as it’s over 20 years old but I guess some idiot could have put a marble in there.
I will fit the new muffler for them this weekend.

 

[CharBaby]

If you’re saying that the vibration is in the rear, I’ve often had to fix the muffler heat shield on vehicles. A rivet(s) that are mounted to that shield, above the muffler(attached to the underside of the trunk) had broken/rotted, causing the vibration. Hmmm IDK, give it a look see!

 

[rob0781]

I find when I have that problem usually soon after my exhaust gets louder or breaks off, it almost seems like it's cracked and causing those noises. Can't say for sure just been my experience especially with older toyotas, 02 echo, 08 sienna and 09 yaris.