I just recieved a new little black D. I noticed that the c note comes out really squeaky. I don’t see any thing in the mouthpiece that needs to be shaved off and so forth. I also noticed that when i put the mouth piece back on it did not quite sound the same. Does anyone know if the mouthpiece should be lined up with the finger holes. It seems to change the sound of the notes depending on the orientation.
I just got a Little Black myself, and almost every note is squeaky for me. Tweaking it a bit, including pouring wax down into the headpiece, seemed to improve it somewhat, but I think it’s just a matter of getting used to it. If you haven’t tweaked yours yet, I’d reccommend it.. there’s a good description of the procedure from Dale linked on the main page. If by “sound” you mean pitch, you probably didn’t push the headpiece down far enough after replacing it. That would make the notes flatter. And yes, the mouthpiece should definitly be lined up with the holes. I don’t know why having the mouthpiece a little askew affects the sound so much, but it does.
Good luck! 
Thankd for the help. I will definately tweak it.
No problemo. Hopes it works out better for your Li’l Black than it did for mine!