2000 Subaru Outback--transmission problems?

Explain your symptoms and let the mechanic go from there.

You may also be due for a timing belt change (105K recommended) and a full 120K service, too. Read the owner’s manual and sort through what may have already been done and doesn’t need to be duplicate through the 120K service. That would get your vehicle up to date for at least another 30K miles or so, less oil changes and tire rotations.