I've owned and driven more 4X4 vehicles than you could imagine and every 4WD that I have ever locked into 4LO made a substantial clunk, I'm not aware of any transfer case on the planet that incorporates synchros into low range.

 

I wished it would clunk everytime - not really. I bumped my shift **** as I got out (engine off.) when I returned it went into 4lo ( without any warning) Since I can't see the **** while seated, it took me awhile to figure out what the heck was "wrong"

all I can take from this is that if you shut off the engine, the shift is almost imperceptable.

 

I couldn't even "muscle" my former Durango into 4Lo from 4Hi without first putting it into neutral & shutting off the engine; so I think I can deal with the "Tahoe clunk".......... - yes mine does it too if in gear, if in neutral no, but at least it works & with a 100K warranty I'm not too worried.