Need Tranny Help - Can you identify these noises

[8t5Silverado]

I am hoping that it is not giving up on me. I will try to explain the noises, but it is hard to do with text. The fluid was a little low, but I topped it off today.

It sounds like it is coming from the flywheel or torque converter. In park, it is a racketty sound, like something is loose.

When I go through the gears, I get a different sound at each gear:

Reverse - Higher pitched "grinding"
Neutral - Not much noise
Overdrive - Not much noise
Drive - Not much noise
Second - High pitched "grinding" just like reverse, but a little louder
First - Not as loud as second, but still a little noise

When driving, it sometimes slips from a takeoff going into second. When going about 30, and stopping suddenly, it downshifts roughly, which I thought might have been the torque converter unlocking, but at that speed I wouldn't think so....

Whatcha think, time for a new tranny or is it something minor.