HI, when my washing machine has a fairly full load it bangs when it goes on full spin, its a Diplomat 1200 spin and is supposed to hold 10K of clothes. It is on level ground.

Martin Owen, April 2008

Sound like the main bearing on the drum needs replacing, when empty rotate the drum put your hand in and spin it, if it still knocks it's the bearing. I had mine done after 4 years and it's coming up to 7 yrears and it's starting to knock when on spin.
My bearing was done under warrenty. Takes an engineer about 2 to 3 hrs to do.

Ross, April 2008