Sounds like the pressure plate height to me. IF you have the old one, measure it and compare to the new one.
Lay it on a flat surface (fingers down), place a flat object across the pressure plate surface and measure.
See if there is a disparity in the two heights (old unit vs. new). Your PTO should engage when the clutch is let out approximately half way.
Lay it on a flat surface (fingers down), place a flat object across the pressure plate surface and measure.
See if there is a disparity in the two heights (old unit vs. new). Your PTO should engage when the clutch is let out approximately half way.