D, when I took mine apart, I found it did not have any gear lube as well. Come to find out, my top seal was shot. The way i found out was to put gear lube in and then work the box a lot. it took awhile for me to get the box working freely, but found gear lube coming out the top. Went downstairs last nite to check wot we used. It was lucas gear box lube. can be used for either rear ends or steering boxes. Sooo, that is wot ours has in it, perhaps someone else has a diff idea. By the way, the seal on top is available at most large auto parts stores if you need one. The grease you see may be 30 year old gear lube that has just had it. But, leave it to the experts to comment.
Brian