That rear trans nut comes out easily with an impact gun, the axle shafts don't even need to be held in place. You just have to unpry those dimples with a pick or small screw driver. Subaru recommends replacing that nut (P/N 802622020).

Also, there's a fix if your throw out bearing surfaces get too worn down:
https://www.ebay.com/itm/PDM-Tranqui...frcectupt=true
I had to get one of these and it works great.