flush the toilet upstairs and a loud noise

[sunnyflorida]

Whenever we flush the toilet upstairs we hear a loud thump noise downstairs. To try to troubleshoot we shut off water to the tank and then flushed the toilet. We did not hear the loud noise. Any ideas on what is causing this and how i might fix it? Thank you all.

 

[Jadnashua]

IF it occurs just as the toilet fill valve shuts off, change the toilet fill valve to something like the Korky Quietfill. Some fill valves can create a water hammer when they shut off. As an alternative (you may not like the look under the toilet), you could add a hammer arrestor. You can get one that just screws onto the connection at the shutoff valve.

 

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[sunnyflorida]

Update
http://www.homedepot.com/p/DANCO-Ba...-Ball-Cocks-9DD0010061/202305802#.UmW09_msiFw

This is what i replaced and the sound went away yeah ;-). It came with a valve looking thing. The one i had was worn out