By "outlet pump assembly" I take it you mean the pump/filter housing. Drain the machine, take out the filter & see if there is anything lurking in there, like coins, buttons or any other foriegn object that could interfere with the pump impellor. My bet is that the pump drive end bearing is worn, the shaft is slack, & this is causing the noise. Only remedy for a worn pump is replacement. Try Whitegoods UK for spares, alternatively there are plenty of spare parts on available on ebay.
Mike
October 2009