My gas oven has a high-pitch whistle when it is on (heating.) A repairman told me I need to replace the regulator and valve. I was trying to locate these parts on my part sheet but am not sure what he is referring to.

Is the regulator and valve one part or 2 separate parts?

Can someone provide some general directions and supplies I would need to do this myself? (His price was just too much in these hard times!)

Thank you very much.
Sincerely,
Suzanne Nielsen