When was you Legacy produced in 2011? Take a look at the plate on the driver's side door frame.
This is the only TSB listed for a 2011:
Service Bulletin # 17-14-11
Bulletin Description: If you encounter a customer complaint that there is a squeak/creak type sound coming from the passenger side, inner seat belt area, the seat belt latch arm may need to be insulated. This sound occurs on the passenger side with the seat occupied, when the vehicle is in motion. The sound is coming from the seat belt latch arm coming in contact with the rear stopper as designed. To eliminate the sound, refer to the repair procedure listed.
This is a 2010 TSB that would have been corrected for 2011:
Service Bulletin # 12-116-10
Bulletin Description: If you encounter a customer complaint that there is slight movement (some customers refer to it as a slight rocking motion) that could be felt in the lower portion of the driver's seat, there is a countermeasure seat frame now available to remedy the condition.
Last edited by minuccims; 03-02-2013 at 06:06 AM..