Hello FitFreakers

I am at my wits end trying to find a "clunk" in the rear end of my Fit. It's a hollow sound clunk coming from under the floor of the cargo area, it can happen when going over uneven pavement, without hitting a bump. Hell, I had it make the clunk when turning hard to the right on solid pavement.

I've changed everything. Shocks were first, followed by the shock isolator mounts, then the trailing arm bushing. I've removed the spare tire and all that goes with it, made sure it wasn't the magic seats, I've zip tied anything lose inside (sun roof vent hoses, wire harnesses). I drove without a passenger side rear shock (havent done with drivers side removed) because it sounds like its coming from that side. I thought that was my fix but it just made it happen less frequently. I've had my buddy (ase master certified) sit in the back, he was sure it was coming from underneath. He also went over the vehicle and is stumped. There's more small things I've done and so far as I can tell, nothing has even made a dent in the volume of the clunk.

If anyone has even any ideas, I'm open to them. Thanks
2017 with 262k miles.

 

Check your muffler and all exhaust pipies.

 

I did a cat-back exhaust replacement in December because I (accidently) tore the old exhaust out. That was my first thought too, but when I grab the muffler tail pipe and shake that sucker as hard as I can, I can get it to clunk a little but it doesn't sound like what I get during my normal driving. I wedged a piece of wood between the muffler and the outer part of the spare tire well to keep it from moving and I still get the sound

This whole bit has been extremely baffling. I'd also like to add that I can't get the clunk to happen when rocking the car while stationary.

I'll be taking another close look at the exhaust, thanks for your help!

 

Here are a couple unlikely thoughts.

1) Any chance one of your rear springs is cracked or broken?
2) Have you serviced the rear brakes? With 262K miles, something could definitely be worn/broken in the drum brake mechanism.
3) Have you ever had interior panels or the door cards out (e.g., to repair a window or door lock)? Any chance something (e.g., a socket) got left behind? There is plenty of space inside the doors and rear hatch for something to rattle or clunk around. Similarly, in the right rear of the car (at least a GE8) behind the small pocket molded into the plastic interior panel there's a pretty large cavity. I'm pretty sure there are also openings/cavities at each back corner behind the plastic interior trim. Anything that got behind the trim could be rattling/clunking around in there as you drive, and depending on the object's shape/size/weight it might take a certain movement to cause the clunk.

 

The rear springs looked great when I had them out to do the trailing arm bushings, I completely redid the rear brakes two weeks ago, all hardware and drum + the wheel bearing. No change. I have had many interior panels off but I am almost certain it's nothing loose like that.

I was certain it was the hatch rattling for a while but I've locked that down as best I can, but that's the area it sounds like its coming from, though it's hard to tell since the rear is basically an echo chamber. I've tightened everything possible on and in the hatch.

I kind of think the clunk has been happening for years but has reached the point where my OCD needs to kill it.

Thank you for your thoughts!