This is a brand new genuine OEM Service manual from Caterpillar for the 3406C Industrial and Marine Engines , for serial number prefixes:
This is the exact same service manual that Caterpillar dealer technicians  refer to.  It contains information on Specifications, Disassembly and Assembly, Testing & Adjusting, Troubleshooting, Schematics, and Operation and Maintenance Information.

This manual normally sells for $613  Don't miss your chance to get a service manual for your machine at a great price!  With Caterpillar dealers charging over $150 an hour plus travel time and mileage for a service call, you'll quickly pay yourself back with this investment!