Hi all. I'm still fairly new here and to X5s. Last night, I noticed when backing out of a parking spot, it sounded like I had an exhaust leak. Steady click/tick sound. When I put it in drive, the "tone" changed, and it went away after I sped up. When I stopped again, upon accelerating, I got a sound that sounded like a relay hung, a rapid clicking sound. It only seems to do it at lower speeds.

I've done some research, but I'm coming up no definite answer. Does this sound like the plastic gear on the transfer case or something else?

I appreciate your patience and assistance!

Oh, it's a 2003 3.0 automatic x5 with around 180k.