sound coming from muffler?

[bobby5]

I have a 05 6.0 and there is a weird sound coming from the exhaust of my truck. Its kind of hard to explain the sound its making. Its like a high pitched exhaust tone. It mostly happens when its cold and only does it aroun 2000 rpms. It sounds like its coming from the muffler. Could it be a heat shield or something rattling?

[Ch2500HD]

It's most likely the heat shield on your muffler that is causing the noise. I had the same problem and it turned out to be the heat shield. If you do a search of this forum, you should find the thread on this topic that will actually give you the GM service bulletin # for this problem.

 

I hope your luck on getting yours fixed is better than mine. I took mine to the dealership twice with the noise. The third time the mechanic ended up tightening the bolts too much and broke the shield. So they replaced the muffler system starting at the cat.