I don't think we're having a good run of luck with the ML270 this week. Now we have grinding/moaning/mild howling noises coming from somewhere up front. It's road speed related, not engine speed related. Location is very hard to pick, but most likely front drive. It sounds a bit like a wheel bearing or a front diff bearing or maybe even a diff crown/pinion noise. The car has had 170,000kms of open road driving. Jacking up front wheels and rotating them has told me nothing. Does the M-Class have any reputation for front diff or wheel bearing problems?