I am wondering what to do with my Limited slip differential?

What is your question?

Over a year ago i replaced the oil in it. I used an oil which should be for LSD. But shortly after the change I have been hearing clunking noises and the LSD works as an open diff. The car: European Toyota Hiace 97" (I believe it maybe called a Granvia in the US) I beleive the LSD is of the clutch type. Can it be worn out, or can the oil not have been completely correct. (oil: Comma LS80-90 limited slip, mineral based)