Shaving is usually regarded as a finishing operation. Applied correctly it is effective in reducing noise due to the modification/correction of the teeth profile. You do not state why the gears have to be shot peened, the gear material or the nature of the stated "Grinding Effect".
Carburised gears, for example, benefit greatly from final shot peening due to a combination of improved compressive surface residual stress, retained austenite transformation and the generation of microscopic 'lubricant pockets'. The optimum peening intensity, shot material and shot size depend on the gear teeth size and gear material.
