I've just arrived back from Genoa in Italy on Ryanair's ex BUzz 737-300 (BZZJ) and it wasnt a pleasent experience!
Shortly after take off, a rumbling noise started beneath my feet (at at the over wing exit) and it went on for about 10 minutes, it sounded like it was a generator of some sort that was faulty (or a fuel pump) anyway, this went away after the a/c gained speed and levelled off at 34000. Then on descent, it started again, and this time was much worse. There was so much vibration that the can of coke on the tray was physically moving! It was also making one hell of a racket, and didnt stop until 5 minutes before landing.
Does anyone know what this is? im quite a seasoned flyer, but have never heard anything like this! it was towards the forward section of the wing area, and central...could it be a fuel pump? If anyone knows, then i'd be interested to know! and also whether its safe?