Here is some info I collected before I decided to use it.

http://www.turbodieselregister.com/forums/archive/topic/1237.html

http://www.xterraownersclub.com/ubb/ultimatebb.php?ubb=get_topic;f=2;t=000625

http://www.quad4x4.com/NV4500FAQ.htm Scroll down to want lube I should use

Where you can get it online
http://www.quad4x4.com/NV4500%20Parts.htm

http://www.gmpartsdirect.com/results.cfm