Jeep Wrangler ratcheding noise

2000 Jeep with AC, 6 cyl, Automatic. I have a noise that sounds like a card in a bicycle spoke, but the card is metal sounding. It goes faster when the engine goes faster. It is not as bad when it is not in gear. It has to have been running for around 60 minutes before it begins. I have replace the fan clutch. The heat sheilds do not rattle. Anyideas!

You cannot get this noise to occur when standing still? That is, I think you imply that it ONLY occurs when in motion. You don’t indicate any relation to what gear you’re in so it should be the transfer case back. Can I assume that you’ve checked the t-case for fluid level.

I’m sorta interested in what this ends up being. I’ve got two Wranglers. 1999 Sahara 5 speed and a 2002 SE auto.