Creaking Noise going over bumps slowly

[Noir]

Hi all,

Need some help diagnosing this problem and looking for anyone who has had the same problem:

Going slowly over bumps the front end makes a loud creaking noise as it dips and comes back up. The noise is similar to a creaky wood floor. The sound seems to be worse in wet weather and the days following wet weather. By going slowly i mean anywhere from 10 - 40 kms/hr

Had it checked and serviced 3 times. The technicians even replaced bushings and I was told every other part was fine. After each appointment, car drove fine ony for the problem to resurface a few days later.

I drive a 2009 323i sedan with 60,000 kms on it. is this normal?? this is my first BMW and don't know much about the mechanics.

Thanks in advance for your help!