Zak W wrote, on Sat, 13 Dec 2014 11:16:52 +0000:

Can you describe the "click" itself? Was it like metal tapping metal; or
more like a "thumping"?

Here is a video of the clicking sounds:
https://www.flickr.com/photos/98287134@N02/15382730574/

Here's what is inside the transfer cases:
Left: https://c4.staticflickr.com/8/7522/1...0301e7ec_c.jpg
Right: https://c4.staticflickr.com/8/7525/1...e9eca41d_c.jpg