tranny noise

Lately my 2000 has been making a strange noise. Never have experienced this noise in all my driving before. Sounds like ball bearings are bouncing around in the tranny. It does it at idle and increases slightly when starting out. It will show up when shifting through the gears when the rpm level is lower. When driving in 5th gear at regular speed it can't be heard, and seems to disappear at higher rpm's in any gear. I considered a throw-out bearing or a shaft bearing, but have no experience as to this particular noise.

2000 what vehicle?

It's an S-10 w/ 4 cyl. engine. Don't know what tranny they used in that configuration.

Did you find out why your truck is making that noise? A little while back I heard a similar noise and I swear my tranny was on the brink of destruction. The sound mainly could be heard in the lower RPMs especially in reverse with the brake on. Do you partake in off-roading? To my surprise when I pulled the aluminum skid plate it was like a shovel full of dirt and gravel. There i could see on the underside of the trans axle vibration marks where rocks where wedged between the skid plate.