Took some time today to pay the 4Runner some attention, and wanted to share some of my experiences with its "clunk".
Before taking ownership of this one, I had only test driven a 2010 Trail without KDSS, and a 2014 SR5. I don't remember noticing this behavior in either of those, but I also wasn't attacking speed bumps in those short drives. I also didn't notice anything like this over all the years with my 3rd gen 4Runner.
That being said, I have noticed very similar behavior in many newer rental cars that I've driven, and an Avalon that a family member owns, over extended periods of time. Nothing was "wrong" with those cars, that I knew of. Of course there are many differences, but I'm also not sure that anything is "wrong" with my 4Runner now.
Here's what I've noticed about the "clunk" over the last ~5,000 miles of ownership:
• Hasn't gotten "better" or "worse" since day 1 (all conditions being equal)
• Front end only
• Affects both driver and passenger side (typically more apparent on drivers side, all conditions being equal)
• While tracking straight forward/not turning (have not tested in reverse)
• While turning (no apparent increase in severity vs. not turning)
• Traveling below 20mph
• Over sharp bumps which cause quick, sudden vertical movement in both directions (your average parking lot speed bump or ruts on a packed dirt road)
• Weather ranging from 30 °F to 80 °F (more apparent at temperatures below 60 °F)
• Sounds and feels like bushing contact, not metal-on-metal, from inside the truck
I think this probably sums up a good part of the testimonies in here, too.
I also captured some video, because I was curious. Like 1engineer had pointed out, simply slapping a go-pro on the 4Runner won't magically show us what's happening or why. But it does show some evidence of what isn't happening at this specific angle (I am considering mounting options for different angles, and am open to requests/suggestions).
<iframe width="960" height="720" src="http://www.youtube.com/embed/rsvuTjwX-E0" frameborder="0" allowfullscreen></iframe>