Exhaust Rattle

I have a 2004 Chevy Avalanche and for the last year or so it’s had a ‘rattle’ in the muffler area (sounds like there are rocks in the muffler). It’s intermitten and does it whether I’m driving or idle. If I push on the tailpipe it stops. It’s been looked at by the dealership, other mechanics and muffer shops and they say nothing is loose and can’t figure out what it is. Any ideas out there what this rattle might be?

Heat shield rattles are quite common, and can often be stopped by tightening the offending shield or a little creative metal bending. Can you crawl under the truck and find the rattle?

Thanks for your reply - Yes, we have been under it and it sounds like it’s right in the muffler itself. One of the mechanics supposedly checked the heat sheild and said it wasn’t coming from that according to what he saw.

It could be from inside the muffler. It is kind of hard to tell from here.

There are baffles inside of the muffler that could come un-spotwelded, it may well be your muffler that needs replacing. Good luck!

some times the exh. pipe is doubbled walledand the inner wall comes loose. a good exh. shop should be able to find it.

Thanks for all your suggestions everyone…I will check out those possibilities!