Alright so I'm not entirely sure whether this is a bad thing or not. When my cars idling you hear a "drop" or "clunk" sound every once in a while. I'm assuming this is coming from the tranny, does anybody know anything further on this?

 

When metal heats up/expands it can make some "clunk" or "popping" sounds.
And since your exhaust manifold and mid-pipe/cat is right next to the tranny, its possible that this is what you're hearing.
You've probably heard this sound after the car was shut off too... right?

 

Nope not when it's shut off, you know the dropping sound you hear when you go from a higher gear into 1st? That's the sound.