On my older 1032 J.D. walk behind blower, the differential has no obvious way of lubrication. On other similar models I've seen a grease zerk installed. Does anyone know how the differential is lubricated? Also, do you think it feasible to drill a hole in the exact location as the ones I saw on other J.D. units and ilnsert a zerk for greasing the gears inside? Let me know what you think. thanks.