do I need an additive in my 8 3/4 sure grip?

jefframin said
Well, I'm not going to remove the chunk. Too much work for such a small problem.

Anybody know what the ratio from oil to additive is, if I was filling one from scratch?

Where is it leaking? It's quite possible you could fix it without doing that. Is it an axle seal or something?

Secondly, I don't know the exact mix, but I think if you top it off and add just a bit of the additive, it should be fine.