Pump or VB - what's that noise?
 

05 Yukon, 260k+ on trans, I bought it w/150k on it and I think it got rebuilt previously. The case is painted.
On shifts or light throttle when cold, it makes a light ringing sound. Like the PR or AFL valve is cycling. It's a continuous noise in D3. If I let off the throttle is will go away. Not super loud. But my old tinnitus ears can hear it with the stereo off. I drive 80mi a day. It shifts perfect. One of these days I'll remember to turn the stereo off when I get stuck in traffic to see if it does it when hot.

I had a guy a few years ago he said it was a metallic buzzing sound. We tracked it down to the pressure control solenoid. He replaced it and noise gone. description same as you give.

Thanks Frank, I'll add it to my next Rock order.
And thanks for the tip on the stove heating of the input shaft for removal. I was a little worried about galling on removal.
I've got an 06 4wd trans 200k+ from a truck I parted out for the S10 swap that will probably need resealed.