I have a 99 Dodge Durang 5.9L 4WD. My issue began after a trip to Fla. I discovered my front tires were worn pretty bad..Im an idiot for not checking before I left however, I replaced 2 tires on the back and moved the 2 tires on the back to the front. I have an issue with alignment that will be fixed by weeks end. My concern is while driving as the speed increases a loud roaring/humming sound begins. I can coast and as speed reduces noise reduces. I put the vehicle in neutral and it does not change the noise. I was concerned with a tranny issue. However while I am driving and the noise is roaring I can go around a left turn and the sound diminishes and even goes away. As soon as the wheel is brought back to a straight direction the noise returns as the steering wheel turns. Any suggestions. I am thinking front bearings from the wheel alignment needing to be fixed. But that is why I am here...

 

could be a CV axle or a bad wheel hub. I would lean to it being a bad wheel hub bearing.

 

yea, my guess would be a bad wheel hub bearing too

 

Wheel bearing, ball joint, or bad tie rod end. You also need a 4 wheel aglinment.