All 3304 And 3306 Engines
Description of Change: The above engines now have new crankshaft assemblies with wider crankshaft gears. The wider crankshaft gears are used with engine front gear trains that have wider gears.
Adaptable To: The new 2W7960 and 2W7458 Crankshaft Assemblies are in effect with the serial numbers shown in the chart. These crankshaft assemblies use a wider 1W4405 Crankshaft Gear. The former 4N7692 and 4N7693 Crankshaft Assemblies had a narrower 7N4525 Crankshaft Gear.
3304 and 3306 Vehicular Engines and most 3306 Truck Engines use a 7N9589 Trunnion Group instead of a crankshaft seal adapter. If desired, a new crankshaft assembly can be used on all earlier engines with the 7N9589 Trunnion Group.
All 3304 and 3306 Industrial and Marine, Natural Gas Engines and a few truck engines, use either a 1W4506 or a 3N1463 Crankshaft Seal Adapter. A new crankshaft assembly can be used in all 3304 and 3306 Engines with the 1W4506 Crankshaft Seal Adapter.
A new crankshaft assembly can also be used in a 3304 or 3306 Engine with a 3N1463 Crankshaft Seal Adapter, if the 3N1463 Crankshaft Seal Adapter is replaced with a 1W4506 Crankshaft Seal Adapter.
The chart that follows gives the in effect Serial Numbers for the 1W4506 Crankshaft Seal Adapters.