After flushing the toilet, the tank fills up. When it is full and the water stops running the toilet makes a howling noise for a few seconds. It may come from the pipes. It does not happen in any of the other bathrooms.

Toilet makes nois after filling is caused by dirt/debris inside the fill valve or loose washer at the angle valve, tell us which fill valve you got see the images below, Thanks.

John

Image 8 is the inside of my tank. Appreciate your help..

Shut the water off under the tank and pop the lid. Unscrew the three screws lift the float ball and the stem assembly up and out, Pry out the washer, hold your hand on top of the open ballcock and let some turn on the water to flush out the dirt out of the ballcock, check the black washer if it looks good clean turn it over and assemble the ballcock, if this would not fix come back and will tell you the next step would be, good luck.

John