hey guys, i was wondering if this is normal

(i will post pictures).
transfer case is not leaking and transmission seems fine. But the area all around it is wet and moisture.
But not too long ago, i was approaching a stop sign up on the hill. As soon as i accelerated, boooom like somebody hit in the back. and since then no problems.
few weeks later noticed this wet area at the transfer case.
Already set up an appointment with San Diego Bmw , would like to know what to expect.
Thank you guys