Tranny question

So, I was under the car changing the oil for the first time when I looked at the bell housing of the transmission and saw this hole on the bottom. I'm told that it's normal so it can breath a little. To me it looks kinda big and actually looks like it has a jagged edge like it's been chipped.

I'm taking it in the the dealer this Monday because I hear a whinning sound when I accelerate/decelerate from 1st though 3rd (probably at higher speeds too but road noise drowns it out).

Here's a pic ...

Thanks