I have a 1999 legacy with about 200K on it. The transmission was replaced (before I bought it) so that probably has about 125K on it. I am having a bit of trouble - my transmission seems to slip out a bit (rare, maybe 1 time a month) while driving - when this happens it feels like the car is in neutral all of a sudden, happened at 50 mph +. More recently I was unable to get the car to go into drive after starting. It would go into reverse but not drive or any lower gears. TO remedy I turned the car off and on a few times and shifted through the gears. Today after stopping at a light the vehicle would not go (like it was stuck in neutral) for about 20 seconds - then slammed into gear and went. I checked the fluid per the owners manual instructions (operating temp, shifted gears, checked) and it was okay. Any ideas? Should I take it to a transmission specialist or a general mechanic?

http://www.ultimatesubaru.org/forum/showthread.php?t=87708&highlight=delayed+forward+engagement

Typical 99 transmission issue, seems to be just that year. For shame whoever rebuilt it and did not replace the seal that causes the problem.

 

The link explains all.