I hear a loud noise, like a squeal when the tank is being filled after flushing. I bought the fluidmaster toilet repair kit, replaced and the noise is still there. My outside hydrant connects behind the toilet in the wall so I replaced the seal cock. My noise is still there. Any suggestions where I may look?
Thanks.

Noise = vibration. Something's vibrating against the seal.
Try this, shut the water off not the toilet and open up the lid. Now twist off the top of the ballcock and remove the black seal,(see image) Now place a can over the open ballcock and turn the water back on for a moment to flush out of the supply and valve. Reassemble and give it a flush. Better now? Cheers, Tom

I did and the noise is gone. Just remembered when I replaced everything that was a step I failed to do. Lesson learned here.
Thanks for your quick response and help.
Tim

No problem Tim,
Glad we were able to help. I you need us in the future we're as close as a click, Cheers, Tom