I have found this on the main site
But cant find anything regarding wether it is a 4.4 specific or wether it applies to the SC. Does anyone have anymore info ?"It is possible that this noise may be the same as a noise (clunk) when the throttle is released and applied on models up to 2007. It sounds like driveshaft play, but is actually caused by the 4.4L engine powertrain control module program which must be flashed. "