I need some help guys, my truck just started making an odd sound last night. I can only hear it at slow speeds with the window down, but it doesn't do it all the time. It starts out ticking like an exhaust leak and it varies with engine rpm like one would, but when you slow down it turns into more of a squeak and I can make it change tones my pumping the brakes like it is a shock squeaking. To make it start I have to give it moderate to heavy throttle but it will not do it all the time. I have almost 90k miles on my truck right now and I always run my BDTD on extreme. Thanks for any help.