I think that the ratcheting sound was caused by a combination of old front differential fluid, as well as by engaging 4wd while all 4 wheels were off the ground. After changing the diff fluid, engaging and disengaging 4wd a few times with wheels off the ground, I have had no further problems with the 4wd, noise-related or whatever. The front-end noises seem to have disappeared as well, for the time being. This TB's got a ghost in it somewhere...

damn gremlins

Have you checked the slop in your passenger side tripod bearing? A lot of play there is the best indicator of a problem with that unit.

I take it you're speaking of the bearing on the CV axle?

I haven't experienced any play to speak of during my wiggle testing of the front end, but could check again. I'm looking into replacing the cv axles just to be safe, and keeping the OEM ones as spares, but for now, they're sound.... no tearing or leaking from any boots, and the noise is coming from the driver's side.

I've sat as a passenger and nothing out the other window. Haven't heard said noise in a few days now, though I think I'm listening too hard now, so that I make myself hear things. I suppose I'll just have to wait until it gets loud again, so that I can fix it.

So for now, I suppose we can mark this thread "Solved" and wrap it up.