Hello, I am Ezzy from Japan.
I have 1988 560SL and worked pretty much everything since I bought my car.
Does the noise exist only when you push the gas pedal or when the car is actually moving?
If it comes out when the car is moving, it could be bearing or wheels.
If it comes out when you push gas pedal even the car is not moving(when you push gas with your transmission is in N position), it could be from Engine, such as fan, mount, fuel pumps, or something near engine.
I had a similar noise when the car was moving so I changed flex disc and bearing to solve the problem.
Hope this helps.

Ezzy.