I like tamiya ceramic grease, or there is auto-motive grease you can use. There is also that gorilla-snawt stuff on ebay, but I dunno what is specific purpose is...
Thats what i was referring to is the ring to pinion gears, regardless, i just made an order from mike with all the necessary parts for the diffs and the center diff mount. Im hopping to have a rolling chassis this weekend.