Thump from 242 Tailhousing

On a 2001 with 4.0/AW4/242 transfer case, I hear a loud bang or bump from the tailshaft housing when the suspension flexes over a bump (as the drive shaft moves in). I thought it was a loose shock, but it is definately the transfer case output, verifyed when I am under the jeep and my son bounces on the rear bumper. With that weird rubber boot and crimped collars, I don't see how to take it apart without loosing the crimped collars. Any ideas on what is making the noise? I would appreciate some enlightenment before tearing it apart.

Use zip ties instead of the steel crimp collars. Just crank 'em down real well.