Reviving an old thread. This may have been answered already but I haven't found it. My assumption is the gasket goes between the backing plate (dust shield) and dust seal per the FSM schematic. My reasoning is brake pad dust. The dust seal is likely there in large part to keep brake dust out of the spindle/hub bearing seal. The backing plate does a good job of keeping brake dust away from the backing plate/spindle interface, and the gasket keeps brake dust from getting behind the dust seal. I could be wrong. Thoughts, please, I'm in the middle of this job and have seen several videos with the gasket installed both ways.