crack it open and have a look. if your not comfortable taking it apart then don't but at least look and familiarize with it and try n see what does what when its "working" youll be able to see worn or broken parts easily.
For someone that are interested in learning a transmission i recommend buying a used one putting that in then download the rebuild pdf buy a rebuild kit off of ebay and GO, check every step 2-4 times.
For someone that just wants their car to roll again go buy a $200 transmission REGARDLESS of the awd application.
I bet you can buy the whole lot for the awd swap for less then it would cost to rebuild your transmission half the time too.
If you need help building, swapping, or fixing your subaru im one source for fellow pnw USMBers.