Steven, thanks much for posting that link!
Many 'play' both forums and forget to post the solution back to one of them. This will keep things in sync as to this particular problem.
He found the root cause is the "Driveshaft adjusting nut" on the front half of the driveshaft got lose.
See detail and picture here:
http://www.clublexus.com/forums/ls430/770272-what-would-happen-if-this-nut-loosened-2.html#post8911244