Nissan ForkLift Engines Service Manual 6BG Diesel description of the catalogue:

Nissan Service Manuals for 6BG Diesel Engines.

This service manual has been prepared to provide necessary information concerning the maintenance and repair procedures for the NISSAN FORKLIFT D01/D02 series.
Any changes effected in the series after publication of this service manual will be announced in a technical bulletin.
It is, therefore, recommended that each relevant technical bulletin be inserted in front of each section and be used together with the service manual as a reference.
If a new model requires different service method or has undergone a major change, revised sections will be issued to replace the applicable sections. Each revised section will include the description of how to service the parts for the former specifications. The publication of a revised section will be announced in the technical bulletin.