Last week I put a new Korky 528 fill valve on a toilet. Now when the tank is filling it makes a GRRRR sounds. Loud and reverberating around the house.

When I google to find a possible reason I read posts suggesting replacing seals and diaphragms. But this is a new fill valve, so I presume all the soft rubber parts should be in good condition.

The previous valve was also Korky, and worked fine for years.

Any suggestions on what could be going on?