grease from drive shaft?

Hi,
Grease coming out of the gaiter is not a major issue, you can repack the CV joint with grease and re-secure the gaiter. The big issue for you is the loud bang. I would strongly recommend pulling the gaiter right back and cleaning the CV joint first and then carefully inspecting the joint. I is not unusual for a CV joint to "knock" when you have the steering on full lock, this is the first sign you need to get it changed, but a loud bang is definitely not "right".
Cheers now

Ken Chapman
April 2007