Loud whistling toilet noise after the toilet is flushed and stops when it refills. Replaced everything inside the toilet already (water fill valve, flapper, braided steel line etc.) No other faucet, shower or toilet in the house makes any other kind of sound. Replaced the hot water heater recently and didn't have any faucet turned on when I first filled the water heater, I was told this could be a cause for the sound. Any info would be greatly appreciated.