ARM AS-UI ROCKER 20R3319 - Caterpillar

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.
It is important to use the correct crankshaft and crankshaft gear, as shown in this article. Use of the wrong parts can result in serious engine damage.
Illustration 1. New 1W4405 Crankshaft Gear.
Illustration 2. Former 7N4525 Crankshaft Gear.