99 2wd auto, started grinding and making a chirping sound about 10 miles from home. I thought it was the carrier/center support bearing. Replaced that and I still have the grinding/chirping/humming. The ONLY thing I can think of is the trans. It actually went away, or seemed like it went away when I popped it into neutral.

 

Hey you ole double poster......I said possible cracked/broken flex plate on your other post.