3.2 Busso powered
AO Gold Member
Join Date: Sep 2005
Location: Abu Dhabi
This sounds like imminent drive shaft constant velocity joint failure.
I've experienced this myself a couple of times (In my case always with the right hand drive coupling), and although the local service agency failed to acknowledge this as a manufacturing fault, my 3rd replacement coupling has been in service for almost 5 years now with no sign of noise or imminent failure, which leads me to suspect that there is (or was) a quality control issue with the driveshaft couplings.
I suggest you raise this issue with your service agency.