help needed,i have an audi a4 1.8 ltr. while driving i get a noise which comes from behind the front wheels, the noise is hard to explain but to me it sounds like an object in a box being shaken, if i was to drive in a straight line on smooth roads you dont get the niose but when driving on uneven surfaces the niose appears,could someone please advise me as what could be the problem,the fault was not picked up in the M O T as part of the failure process and the garages that ive been to cant seem to identify the noise. my hope is to narrow the problem to possible one thing without paying for other possible causes without fixing it.many thanks in advance.