i agree about the grease hardening up over time. i resurrected an old used suntour freewheel that hadn't been used for years, and it was silent as well. after injecting some light oil inside the freewheel body, the pawls got noisier... but the other thing that happened is that is sounded rough, or "gravely". i surmise that there was dirt and grime in there that got loosened by the oil and the bearings were now rolling on freshly loosened dirt. but that won't happen with a NOS unit!