Clicking noise after coming out of 4WD

[rgoers]

2001 Sportage...

When I take the vehicle out of 4WD, I get this loud clicking noise coming from underneath. I can't figure out exactly where the noise is coming from, but it does not sound good. It's tied to revolutions, as it gets faster and slower depending on travel speed. If I stop, and back up and go forward (then back again) a couple times, it goes away. It only happens when coming out of 4WD. Otherwise, the 4WD seems to be working fine (I've driven it around in sand to test it).

Any ideas...???

[rgoers]

In case anybody is following this thread - I solved the problem today.

It turns out that there was a small (roughly 2"x3") plate spot-welded to the drive shaft which runs the front transaxle. I'd guess it was perhaps a balancing weight, but I'm not sure. Anyway, the plate rusted loose and was hitting against an adjacent transmission line clamp. I'd imagine if I hadn't removed the plate, it would have eventually flown free and destroyed the transmission line right next to it.

So the plate is off, and the noise is gone.