I have one of these on my cruiser bike....and it had some problems in the beggining and was told... 1) do not take it apart 2) do not lube it....any problems send it back under the 2year warranty with shimano..those things are like clockwork inside and noone really wants or knows how to work on them......but I would tinker with the alignment of it first... making sure the yellow line is where it is supposed to be while in the middle gear ( I think its the middle)....otherwise send it back....