Override Biped Animation

I need to override my character’s biped animation while it’s playing. It’s a third person game and when my character looks up, the camera goes to look up, but the character’s head/upper back doesn’t rotate to follow (I have a script that affects the bone transforms to look at a target object).

I tried using LateUpdate() to rotate the bones towards the object, but still nothing happens. Does anyone have any suggestions?

See the locomotion system and the Head look controller. Its a combination of moving transforms, blending animation, and adding mixing transforms to the animations. It can be complicated to figure out without an example.