Shimano makes awesome reels, but every reel needs a cleaning once in a while.  I fully take apart the reel once a year and clean it before putting it up for the season if I only fish fresh water with it.  However when I fish saltwater, it needs to be done more often.  This also should be done if the reel gets dunked in water, especially saltwater.
 
Part 1:



Part 2: 

 
Part 3: