I have an 06 with 28000 miles on it. It has a strange noise coming from under the truck. I dont really know how to describe it other than a "wamp wamp wamp" sound. It only happens when I am going over 35 and it gets really loud from 40-50mph. All of the gauges are fine and Im not getting any codes that I know of. It does this whether I am in the throttle or not but it isnt nearly as loud when its coasting. Any ideas?