So I am driving my 06 Commander home the other day down the local highway at 50 mph, and I come up on a set of railroad tracks. I have gone over these tracks hundreds of times before. This time when I hit them all of a sudden there was the God awful noise coming from the drive shaft or transfercase area. The noise was speed related because as I went faster it was louder and faster. I crawled under and I didnt see anything loose. It had sounded like the driveshaft had come loose. I was only 2 miles from home so I decided to baby it home. By the time I got home it was extremly loud. So I backed into my driveway and crawled under again, nothing. So I decide to put it in 4 wheel low to see if that made a difference. So before I put it in 4 low I pulled foward into my street and didnt hear anything, weird. I put it in 4 low and I still didnt hear anything. put it back and 4 high and the noise all of a sudden fixed it's self. I drove it all around yesturday and this morning and nothing...WHat the hell, I dont want to bring it in because it is 1500 miles out of warrenty. Any ideas?