Yeah, best thing I can guess is when the case stopped going into 4x, that the fork itself broke off IN the case and just stayed out of the way until our shakedown trip with the trailer.
*I* heard, wife didn't hear, an odd whining noise.
Stopped, nothing found, no drips.... then on the way back from Pahrump to where we're at now, it (the noise) stopped.
Get home, find that.
so, best guess is broken piece finally moved into position and interfaced with the chain, self clearance-ing once it got to a point it couldn't move past and got forced out through the side.
I already have a replacement rear half from merchant, it's just a matter of getting it all out from under the truck in the driveway, in nevada, in late summer where the tools left in the sun as you change from socket to socket will burn your damn hands.
Suburbank2500.... 2004 crew cab duramax, ie 2500hd, pushbutton transfer case.