Hey guys, I have a 2010 JKU Rubicon with a BAD rattle that appears to be coming from a black plastic ribbed box with a white cap on the backside, that is mounted to the undercarriage slightly offset to the driver's side about halfway between the transfer case and the rear axle. If you tap it with your knuckle, it sounds like one of those rattle instruments from a middle school music class.
FYI, the Jeep is operating fine, the rattle does not seem to be linked to any performance issues or breakage.
Do any of you know what that box is or have you experienced the same thing? Thanks! Matt