Nimyad its called clutch chatter, its actually a "bent clutch" sometimes when replacing the clutch the transmission becomes hung-up when re-installing it and it puts A Lot of weight on the clutch disc, this actually bends or warps the metal ring in the center of the disc. The only fix is a new clutch disc. I accidentally bent mine cuz my clutch wasnt aligned enough. Its no big deal though wont hurt much , just wear the clutch a lil faster, big whoop