We have a Hotpoint Aqualtis 9D 1600 spin washing machine that started to make alarming knocking noises when it went into the spin cycle. The machine is only just over 12 months old but the problem turned out to be the front counterweight that had disintegrated, and this in turn had caused damage to the drum assembly. I know this isn't exactly the same machine model as yours, but the same principle might just apply!
For full details and pictures, visit my blog at http://grumpygitsandusefultips.blogspot.com/
Read more: http://www.diynot.com/forums/viewtopic.php?t=259435#ixzz1NeZ61LRB
Smugdane, May 2011