check your motor mounts and drive-lines ( U-Joints ) , there should only be a light tink noise from slack in driveline . sounds like you may have something going on under there thats not normal
i hope its not too major , hang in there hummer will get it fixed . you might crawl under and have wife or someone shift for you maybe you could isolate the area the noise is coming from .
keep us posted and good luck
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