Overrunning Clutch
WARNING: This page is about a different car, the 2006 Subaru Outback and 2006 Subaru Legacy. However, it is still accessible from the selected car via links, so may be relevant.
Check that there is no wear or damage to the piston teeth. Replace if damaged. If it rotates smoothly when rotated in the correct direction (counterclock-wise) and does not return to the other direction, it is normal.
CAUTION:
To prevent spilling of grease, do not clean the overrunning clutch with oil.