My UN54 is making a lot of noise too. I bet it's the damn plastic cup moving around, at least that's what it sounds like. I'm going to take it apart and slather it and the BB threads with a thick coating of synthetic grease. I'll probably end up buying one of those metal cups for it eventually. Shimano should include a metal cup and increase the price to cover it. The plastic cup is enough reason to buy another brand instead.