Ultramax Noises

[KarenMind]

When I flush our new Ultramax toilet, it sounds like something is squeaking really loudly - the only way I can think to describe it is it sounds like a seal barking. Any ideas on what might be causing this. Other than the noise, this toilet is great Thanks for your help.

 

[Jadnashua]

Might be the fill valve or the water supply shutoff. Is the shutoff fully opened?