We're on our 2nd set of filler plates for our 8820 that is used mostly in corn and beans and occasionally wheat.We believe strongly in them.They're meant to help keep the crop mat pressed between the concave and raspbars and to keep it moving rearward.Having small bits of crop or residue inside the cylinder would serve no useful purpose.We also have golf balls inside the cylinder (one ball per section of raspbar/fillerplate holder).We got this idea from a JD mechanic.The balls fly around inside the cylinder to keep the dust and debris from taking a set against the raspbars and filler plates.They work slick for this and we've never lost one or had one break up.
To eliminate the vibration/rumble a cylinder makes when starting up,we "feather" the separator engagement lever to slowly turn the cylinder so the dirt can fall out between the gaps between the raspbars and filler plates.Then we fully engage it and go wide open throttle to move it on out the back of the machine in huge cloud of dust.It's best to do this when you shut down for the night so it's ready to go the next day.
If I remember right the 9000 series filler plates might have narrow slots cut in them so the dirt falls out of them easier.And with an electric separator clutch there'd be no way to to feather it on.It's either on or off with a bang on these machines.

If I remember right the 9000 series filler plates might have narrow slots cut in them so the dirt falls out of them easier.And with an electric separator clutch there'd be no way to to feather it on.It's either on or off with a bang on these machines.