[psheehan]

Tball,
I'm not an expert at this; I'm a new hitter myself (13 months)
However I will share my experience and maybe you can identify something that will help. I have problems with hooks when one of the following occurs:

1. not stopping at top... bends the plane line and for me shuts the face.

2. poor extensor action... this causes a bunch of impact problems but hooking is high on the potential problems list

3. right shoulder moving out instead of down plane...and usually this is associated with #1 above.