What causes vibration in the older style Kiln Vent that mounts under the kiln?
1) The kiln is not level.
2) Dirt has collected in the squirrel cage.
3) Moisture has corroded the squirrel cage unevenly, throwing it out of balance.
Orton sells a gasket that reduces vibration from the motor. The gasket fits between the vent and kiln.
To make the vent last longer, regularly vacuum the kiln interior and the floor under the kiln.