Hey Mike, something to note after rereading your post (it really sounds like it's going to be your transfer case). You might want to attempt resetting the transfer case adaptations, driving for a couple days, then pulling codes again.

Mine never threw a code until after we attempted a fluid flush and fill on the transfer case. After that, they reset the adaptations and a few days later it had thrown a code, 5F3A, which is "Transfer Case Internal". The indy had visually seen the vibration from the transfer case, and this kind of confirmed that we were headed in the right direction.

Perhaps resetting the adaptations and checking codes again will bring it up.

__________________

• 2008 X5 3.0si Alpine White