I've just finished a new washing machine help article on Whitegoodshelp. I recently had to repair my son's washing machine. It was making a strange tapping, rattling sound when the drum revolved. It was much louder on the spin cycle. At first I was puzzled and was unsure what the noise could be. When I pulled out the washing machine and took off the back panel I could see that the drum pulley was loose. It was still securely fastened with the pulley bolt, but the centre of the pulley had badly worn.
Full story with videos and sound can be found here rattling tapping and grinding noise on spin