MANIFOLD 2P5778 - Caterpillar

3400 Series EnginesSome servicemen have not been sure which main and connecting rod bearings to order for use in 3400 Series Engines. The reason for this is that they have at times tried to order the part number shown on the bearing itself or they have checked for that number in the Numerical Parts Record (NPR) and it was not listed.
This has happened with the 1N3542 Main Bearing and the 9N6321 Connecting Rod Bearing. These bearings were used for a short period of time and are not currently used at the factory. A replacement for them is the 8N5421 Main Bearing and the 8N5426 Connecting Rod Bearing. The NPR will be corrected to show the former bearings and their replacements.
The Parts Books show the correct bearings to be used in these engines. Always use the microfiche Parts Books because they will show the latest parts to be used in each application.