Turns out the used transmission I installed on the forester had a bad center diff, so I swap out the one from the old transmission to solve the issue
00:00 - Intro
01:07 - Salvaging Center Diff From Old Transmission
03:57 - Prepping To Remove Bad Center Diff
05:04 - Removing Transmission Cradle
05:49 - Disconnecting Shifter Linkages
07:30 - Removing Bad Center Diff
10:21 - Installing "New" Center Diff
21:33 - Discussing Subaru Diff Issues
25:08 - Gear Oil Type Matters!
26:13 - Testing
27:13 - Outro