Fits Caterpillar 638, 3306 PC Crankshaft New 6 Cyl Diesel 1P1390, 5C3836, 1P1391, 5C3837, 1W8356, 5S5870, 2P2824, 5S5871, 2P2842, 5Y1546, 2P6219, 6N8079, 2P6221, 8M4502, 2W7458, 9S2270, 2Y5206, 9S3057, 2Y4507, SP6222, 4N7693, 0R5018, 4N7696, Y4517, 4P9857 For Precombustion (?PC?) engines. Main thrust width on this crankshaft is 1.685?. Front timing gear has 40-teeth and is L/H helical. See also part # 5423N * Flange: Flat, 9 Bolt Holes, 1 Dowel Hole * Snout: Tapered, 1 Bolt Hole, 1 Keyway * Stroke: 6.000" * Rod Journal: 2.9987-3.0003? * Main Journal: 3.4990-3.5000? * 7 Mains * With Helical Gear