ASD is great - it is a hydraulic locking diff which engages at speeds up to 19mph if wheelspin is detected. The rest of the time it's a normal LSD. It is NOT traction control, however. If you want the tires to stop spinning you need to pull your lead foot off the pedal. And, as the diff clutches wear, the LSD and ASD function decreases. When the clutches are worn out, it will act as an open diff even when ASD is engaged. New clutches will fix the problem.
Detailed info on ASD is available on my website
here and
here. Those links also explain the difference between ASD and ASR (ASR is true traction control).
