The muffler heat shield may become loose on the muffler causing a rattle or popping noise. Our technicians tell us there is a kit available from GM to correct this problem.Google+
Car Problem Reports
Chevrolet Silverado 2500 HD Popping Noise From Muffler Heat Shield
Chevrolet Silverado 2500 HD Problem
Exhaust & Emissions Affected: Gasoline
Average Mileage: 106,515 mi (5,000 mi - 204,000 mi)
Visitor, 2005 Chevrolet Silverado 2500 HD, 67,500 mi
"vibration" type rattle at around 2200 rpms. The truck has to be under a load meaning in gear. Just revving the engine, in park, will not recreate the noise.
Visitor, 2001 Chevrolet Silverado 2500 HD, 200,000 mi
The heat shield on top of the muffler has come loose at one corner and now makes an annoying rattle with the engine at an idle. While cruising it usually goes away, however can still be heard at some RPMs.
Visitor, 2001 Chevrolet Silverado 2500 HD, 105,000 mi
Popping noise from muffler heat shield. Mechanic removed the heat shield.
I have a rattling sound that comes from my heat shield, after the truck is warmed up it goes away. I have yet to have it repaired because it only does it when it's cold and I first start it.
Visitor, 2002 Chevrolet Silverado 2500 HD, 108,000 mi
Muffler seems to hum, sounds like a faint train when truck is started. After it warms up, sound goes away.
Visitor, 2004 Chevrolet Silverado 2500 HD, 150,000 mi
Thought the muffler was bad, it raddled at low speeds, the muffler guy fixed it for $10.00 and said it was a loose piece.
Visitor, 2004 Chevrolet Silverado 2500 HD, 5,000 mi
rattles at idle, sometimes.
Visitor, 2008 Chevrolet Silverado 2500 HD, 100,000 mi
Popping noise from exhaust
Visitor, 2005 Chevrolet Silverado 2500 HD, 129,000 mi
same as above
Visitor, 2004 Chevrolet Silverado 2500 HD, 105,000 mi
Getting popping crackling noise. Not fixed yet.