I only heard it once or twice when the Hummer was new, 10 months 14K miles ago. I didn't think much about it, thought just the hot pipes cooling down under the brand new Hummer. Never heard it again since then.

Mine does this too. It is really loud! I am going to get the parts and try to fix it myself.

Cheers

[ formerly known as wannabe and wannabeinit ]

MAC, Mine popped once or twice also. Then went away ! On further inspection it appears some road kill skelatons are now keeping everything tight and in place!

Mine does not pop or rattle but my Escalade has this awuful rattle sound when in OD with the converter locked up. It has the same muffler as the H2. Thanks for the TSB Klus.

The only issue so far after 3000 miles is the clunk that happens about 2 seconds after you accel from a stop.

03 Sunset H2!
89 Vette
02 Escalade