Did you try adjusting the station it broadcast to? I thought the FM transmitter was crap until I messed around with the different stations.
Just don't do it people. Me and so many parents have horror stories. Even without social media these phone numbers get out one way or another. For us it was much more trouble than it was worth.
I remember the monsters inc DVD had Sully using boo as a bowling ball in one of the bloopers and I found it hilarious as a kid.