Coming back from a camping trip with the truck camper I started noticing a whining sound from the front end. I removed the slide in and the noise is the same. First sounded like an exhaust leak but I'm getting a slight vibration in the steering wheel. The noise is constant above 50 mph going straight but turning the truck into a right curve the noise goes away. I'm thinking front axle bearing but its just a guess. The truck has 46,000 miles. Any ideas or suggestions on what to look for?