The noise is right around the 5.5 second mark in the video

 

Thanks for checking in! I did watch your video. Yours is a different issue, I think.
Mine is behaving more and more like a u-joint, but doesn't sound like it. (As stated, I always think U-joints are a single "clunk" or "thud" whereas this is a single "click"-- but is definitely mechanical, not electronic, at least it doesn't sound that way...)
As per my dealer, I'm driving it until it becomes constant and easier to diagnose.
HOWEVER, it now can be heard (again, with the top down from the right side of the car) when accelerating from a low speed, and sometimes taking my foot off the gas and slowing suddenly, again at a lot speed (10-20MPH). And sometimes when shifting into our out of drive when stopped.
And it's getting louder. Still a SINGLE "click" sound, though.

 

I spent some more time on your thread... my issue sounds like what myexcursion described almost exactly.

I should point out that I had my entire differential replaced, and I do not remember the sound before....

 

Any updates?

 

Thanks for checking in!
Not yet - I will say it's getting worse-- it's not louder, but happening with greater frequency. I'm due for an oil change in a week or so and that's when it's going to be checked and I will let you all know...

 

I wonder if it's a rear sway bar end link. I noticed when my car was on the rack that my boots are torn on the end links. Then again, I would think you'd hear a constant rattle over bumps, not just a click.

 

So, it was... a wheel bearing.
Which makes ZERO sense to me.
But they replaced it, and it went away.
Having said that, they also replaced front control arms at the same time. I suspect that was the issue.

 

 

Interesting. The wheel bearing cause doesn't make any sense to me. Front control arm makes a little more sense, but i think the subframe bolt sounds more likely.

 

I'm about to take the XKR out of storage--I'm going to try to tighten that subframe bolt to see if it makes a difference. It appears to be the right rear.

 

I agree it sounds odd.
All I know is that I had the problem, they replaced the bearing (as well as the control arms)... mystery click is gone. I'm only out the $100 deductible for the warranty. Works for me.