Just finished changing my transfer case fluid. Had a code for expired fluid and had a liter of the expensive bmw stuff sitting on the shelf from an e83 x3 purchase a long time ago. Cleared the code but haven't driven it yet. Curious to see if I notice any difference in driveability. I've experienced some random vibration at different highway speeds as well. Usually smooth but inconsistent vibes around 60-70 mph sometimes.

Yup. Plus the transmission whine type of sound when cold.