David,
Saw your excellent utube’s on transfer case chain replace BMW X5.  My X5, 2008 5.0si (6 cyl) once in a while lets on a clunk a couple seconds after starting in park, and lurches back a couple inches!  Very strange…scary when it moves in park!  Could this too be transfer case issue?  Thank you!
2008 X5 3.0si   110,000 miles