2015 Bed Rattling???

I've had this awful bed rattle for the last few thousand miles probably, and I've finally traced it back to, or near, the back right bed bolt (closest to cab), I've tried tightening down by hand with breaker bars and even put the T-55 torx on an impact gun, still never budged. Just curious if anyone else has had the same problem or knows of a fix. I'm currently at about 23k miles so it'll be going back to the dealership soon if nothing comes up here. I'll attach a few video clips below, mostly for sound because it's kinda hard to hold a camera steady while riding in the bed on a bumpy gravel road, at a few points in the video it appears as if the bolt head moves up and down but that's actually the bed moving, just try to watch the gap between the washer and bed. Thanks in advance!

 

I had the same problem, just figured it out today.....it was the shovel under the truck box banging the bed end below the rear cab window. Moved the shovel away and rattle disappeared.......not being a smart ass, but do you have anything loose in the bed, tool box not tightened down, etc?

 

I bought a tri-fold bed cover, then I started noticing the rattle more, so I took it off, it still rattled, I've take everything outta the bed, outta the cubby boxes, hell I even took the cubby box doors off and it still rattles, I can't get my videos to upload for some reason...might try YouTube and post the link shortly. Thanks

 

https://www.tacomaworld.com/threads/tacoma-loose-bed-design-flaw-explanation.388873

 

Nice!!! Thanks a lot! I'll be sure to look into it as it seems like a simple fix!