2001 Jeep Cherokee humming

My car is making a humming sound that can get loud and then gets lower when I am giving it gas but then will get loud again. Its coming from the front and will do it when stopped also… Any ideas? Its a 2001 Jeep Cherokee Sport 4x4 4.0 liter…

You hear the noise when the car is not moving? in neutral or park? how about when the engine is turned off? Does it change when you rev the engine in neutral?