The diff. grease (white clear color) is too light/thin for differential. The black grease (you apply to susp. ball) is too heavy/thick for such differential ball.
So what you need is somewhere in the middle in viscosity (near the black grease I prefer) for use when building differential gear.
I'm using Omega Brand (do not know the part number since it is given by local friend) and uses differential sticker cover (I believe Atlas make one for TA04 which is the same with 414M, but you could always made one yourself).
Has been tried in one day practice + 2 days race without cleanning and proves to be running smooth, still.
This idea may not be new, but I do not recall reading in this thread. Shouldn't be wrong to mention then
Edited: Lubricant Enggineerings, Inc - General Purpose #1223 should works fine.