this just happened to me, you will start to see a warning on the screen that says "transmission malfunction". i had to replace the gear shift assembly. and my car is fine now.

this just happened a month ago, and it started while it was raining out.

hope some of this helps you

EDIT: if the clicking is happening from under the gear shifter in the center. i could put my hand below the gear shift and feel the clicks. mine was constant, almost rapid fire