Rear suspension clunk (w/ Video)

I've got a rear suspension clunk that happens when the suspension travels down as if it goes through a washboard road or something similar. First I thought it was the shock mount, well nope, I swapped it out and the noise is still there. The spring isolator rubbers are in good shape. everything is torqued correctly. RTAB's are good, sway links are good. Its a solid type noise.

http://ift.tt/1rbceAB