I have a 2002 E55 that is making a clunking noise from the left rear suspension i can see nothing loose back there it only makes the noise when i have load in the rear of i hit big bumps any ideas as to what can cause this?

 

Exhaust is the usual culprit but it could be many things.
You need to get the car on a ramp with the vehicle loaded so that you can check out clearances between components safely.

Has the vehicle has a new exhaust or rear end accident repair work done on it? This would reinforce this possible diagnosis.