I have a question regarding what happens when I flush the toilet in my Master Bathroom. I notice that when I just flush the toilet, with nothing in it, the pipes don't rumble......but when I put anything in it, like tissue, etc., the pipes rumble for about a second. Now I notice the same thing is happening with my other bathroom on the same level. Any thoughts? I was told by others that it may be a bad fillvalve in the toilet tank and possibly a bad stop ***** behind the toilet. Since I was planning to do so anyway, I went ahead and replaced the WHOLE toilet in my Master Bathroom. I also replaced everything inside of the tank. I even replaced the stop ***** (stop valve) with a quarter turn stop *****. I made sure I checked for leaks after installation....everything looked fine. Much to my dismay, when I flushed tissue down the toilet, after all of the issue goes into the toilet, I hear the same thunderous rumbling in the pipes (which lasts about a second). Any thoughts?