Is there a reel that is considered sealed that you could fill with oil.  I used to race rc's and the diff's were like that and i kept them very smooth.  If so does it involve a gasket of sorts.

there is a JDM daiwa reel to be released this year that has a fluid seal. i think the internals are likely greased, but the seal is apparently very advanced and owners of the reel would be required to send the reel to daiwa for maintenance.