Is the noise coming from top or bottom rear area?
Hopefully an adjustment to the tail gate will fix the issue.
Subaru now acknowleged that their Outback and Legacy wagons might have a spot weld failure during the manufacturing process. Check this out!
http://legacygt.com/forums/showthre...gon-gt-spot-welding-point-failure-132510.html
Subaru issued a repair procedure to their dealers to carry out additional spot welds. However this procedure is a piece of crap.
This kind of weld failure also occurs from the rear roof area. A number of vehicles have be recalled to rectify this same problem and sadly in some cases, noises still evident after re-welding.