Originally Posted by FBinNY

A film of heavy grease would quiet it slightly, but more could interfere with proper engagement.

The problem is that this hub doesn't have pawls. the clutch id made of two mating tooth discs with sawtooth profiles. They're held together with a spring, and the moving mass is much greater than a two pawls.

So it makes noise like a round of applause when you coast. Greasing makes it sound like a round of applause wearing gloves.