Newbie here, so forgive me if this has been answered. I searched the past threads but couldn't find anything.

I have a 99 Legacy. 2.2, auto box, 124k miles.

Sometimes, but not always, the tranny doesn't want to shift from drive. It just hesitates, and eventually goes. Revving the engine seems to make it take, but I have a feeling that's a bad idea. Fluid is full and clean.

A friend suggested it could be vacuum lines, and that kinda makes sense. I looked and did see what appeared to be vaccuum lines running to the 'box, but wasn't sure, and didn't really know what I was messing with, so I left it alone.

Anyway, I ask the experts here: Any ideas?

all the newer automatics are not controlled in any way by vacuum. They're all electronic.

I know you said the fluid is clean, but when was the last time you've changed it? Also, how are you checking the level? Car running at normal op. temp, and have cylced through the gears.

i would change it again