Think this should be what youre looking for
https://www.subaruoutback.org/threads/new-front-differential-drain-plug-gasket-803926090.45135/
https://www.amazon.com/dp/B00IGZQA3W/ref=cm_sw_r_cp_apa_glt_fabc_MX9RCWJP6Y13H1CMG5FC
803926090