I have noticed a loud creaking noise coming from the front end of the vehicle. It doesn't happen when I start driving the truck, but I notice it after driving for a little bit. The noise only happens when the tires rotate and it speeds up as the tires rotate faster. It doesn't sound anything brake related cause it doesn't sound like metal parts. It almost sounds like a power steering/suspension noise, but the power steering fluid is fine and it happens when I am going straight on flat ground. Any ideas??