Copied from NewAgTalk: We have had great success this year running the 23 and 2588 in soybeans. I put the 99 2388 on the corn head and after setting it up, went to the field. There is a very unusual noise that is coming at the front of rotor?/feederhouse? area that I can't track down. It only occurs when going at about 4+ mph in corn 8 row 150+ bpa corn. It only makes this noise when running a decent amount of volume in the combine. I can feel the noise on my feet at times. Sounds like a clank of metal on metal. It really sounds like the feeder chain jumping teeth, but the feeder chain is tight and we made it tighter but didn't help. Could it be the drive teeth are shot on the feederhouse??? I can't see any vanes loose in the cone. They have been replace and I welded to them even after I bolted them on. Combine has about 1700 sep hours and original feeder sprockets. I don't recall if I reversed them when I pulled the rotor a few hundred hours ago. I have also heard about the hex shaft wearing that drive the sprockets. I don't notice an effect on performance when I hear this noise. It can occur about every 2 seconds when pushing it, but not consistently every two seconds. It kind of sounds like a very big cogged slip clutch. I checked the concaves and they are secure on the left and right. Front rotor bearing, don't think so. It sounds like feederslats hitting something. Smooth as silk empty. What do you think. If I can't find it, I guess I will just run it until it breaks. Dad said it reminded him of the sound of corn when using the conventional gleaners back in the day. Thanks.