Being overfull of fluid will cause your fluid to airrate and act is if you aren't picking up fluid since there will be nothing but air bubbles being picked up, also it will cause it to vent. If you are a tad above the full mark when it's hot prolly won't do much, but I wouldn't want to be too much overfull. It's very common for a tranny to suck up fluid as it runs through the gears and fills up the converter all the way. When I start with a dry trans I usually fill it up, till it's on the dipstick, then engage it into forward and reverse, and then I check the fluid again, because it will suck more fluid up, then I test drive it and check it again. As far as noise from being overfull of fluid, I can't really say it would make noise, since I really haven't payed much attention. I suppose if it was really arrating the fluid you could hear the pump whining, but that is just speculation. I'm assuming you didn't change the ring gear with the differential, so maybe you are hearing the whine from it not being a matched set. I've used unmatched sets before with no problems, but you never know. Is this whine still a constant whine, that doesn't seem to matter if you are moving or not?
