One problem related to suspension noise has been reported for the 2004 Cadillac CTS. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2004 Cadillac CTS based on all problems reported for the 2004 CTS.
Under power the rear suspension rattles up against the floor. It sounds like its falling apart which prompts you to stab the brakes upon hearing it.