A helical LSD includes a case defining an inner cavity and a plurality of grooves disposed around the inner cavity. In addition to the case, the helical LSD includes a plurality of pinion gears. Each pinion gear is disposed in one of the grooves and includes a plurality of gear teeth. Each gear tooth has a top land. The helical LSD further includes at least one helical output gear disposed in the inner cavity of the case. The helical output gear meshes with the pinion gears, and the pinion gears are disposed around the helical output gear. The top land has a surface profile characterized by raised portions and indentations in order to minimize noise and vibration when the pinion gears rotate relative to the case. The surface profile can also be applied to contact surfaces of power transfer units and transfer cases.