Transmission/Transfer Case Question
 

It's my understanding that in the 4Matic in my w166 the transfer case is integrated into the transmission. Does that mean they share the same fluid? So when I change the transmission fluid it's also changing the transfer case fluid?

Is there a center differential or is that the same as the transfer case?

There's only a separate transfer case if you have the on/off road package with low range.

This also begs the question does the ML requires a TC drain like the W204 when a transmission service is done? Does the ML's TC have the mystical drain bolt that most service centers deny that even exist on the 7g transmissions?