Why is my transmission making a clicking sound if the vehicals keys are NOT in the ignition?

I havent drove it for about two weeks and I opened my car door to get a wrench (didnt touch anything on the dashbord) and when I shut the passenger door it started making a loud clicking sound.
i looked at the console above the tranny and found an access panal under the ebrake lever. I opened it to find a black box above the tranny where the noise was coming from. There is no way to open that black box, from what I can see in the access panal. Any clues as to what maybe the issue? And thank you for your time.