when the car is stopped and you can put it into 5th and let the clutch out without anything happening...
mine went really fast when it went. one day I smelled burnt clutch, the next day it was parked
try to do it yourself, cause if you can't, you'll probably be paying $800 +...I got hung up on mine because the starter bolts were seized on. I had everything else out...unfortuanately I didn't have a good torch, so I had to pay a shop to do it...$600 later....