Anyone experience interior clunking from passenger side?

I noticed this since new but it's getting worse. To this point I thought it was things in the tray behind the back seat.

Every time I hit a bump with the back wheels, I hear a clunk from the passenger side. To me it sounds like it's in the post or pillar. I tried to buckle the seatbelt with no passenger, but no change. Oddly enough, if i have a passenger in the front passenger seat, the clunk goes away! I'm wondering if it is the weight on the top of the seatbelt inside of the pillar that allows the seatbelt to lock up when g forces push it forward?

I've checked under the seat, behind the seat, under the back seat, and made sure that it is NOT the seatbelt buckle banging against the pillar.

Any suggestions?

 

I think I got it resolved. I made an appointment at the dealer tomorrow, in prep for that I took a box full of stuff out of my truck. Flashlight, can of brake cleaner, can of window cleaner, ratchet tie downs, tow strap, and an umbrella.... Guess what, no more rattle! I was positive that it was in that seatbelt post, now it's gone! I changed my appointment to taking in my Camry in for a recall on the window switches.

 

UPDATE: the first cold day that we got, the noise is back! I thought it interesting when the service tech asked me if it only happens on cold days, it was 55 that day. Today it's 27 and it's making noise again. I have an appointment next Monday.

 

I don't think temperature is a factor here, but are the factory Toyota tire changing items secured within the under seat areas of the rear seats?

 

I had a similar problem with my 98 Camry and it turned out to be a missing tie rod bushing. It was pretty easy to replace.

 

Yes, the jack and accessories were on my initial list to check. The tech mentioned a seatbelt bolt in the post has been the culprit on some.

 

Did you get clunk taken care of? I'm having the same issue with my 2015.

 

I just got back an hour ago from picking it up. They were unable to duplicate it but the tech did some adjusting inside the B pillar, I assume with the seatbelt bolt. I have read that the seatbelt bolt has been the source of this with others.

As of the ride to the shop and back, it hasn't made a noise. It seemed to be more likely to happen when it was cold outside. It was 29 on the way in this morning, 63 on the way back with no noise to or from.

Before you take it to the dealer, empty everything out from under and behind the seats and from your overhead console. You'd be surprised how noises happen and you can't identify where it's coming from.