Ben you have a center Spider diff (unless you bought and fitted one today). The give away is the word SPIDER written on it. And you only run grease in a Torsen, or 1000 wt max.

Anyone else wondering A good starting setup I find is 3000wt Front, 5000wt Center and 10,000wt rear. These are all Silicone Diff Lock Oils. And yes you could run shock oil in there but it is so thin that the car would handle like crap and the diffs would need rebuilding every session.