I wouldn’t add any to start......because....
1) your fluid already has modifiers in it.
2) cone type differentials do not seem to be as “demanding” about additive as clutch type
3) it’s easier to add it than take it out.....if your diff experiences chatter or other issues then add it later
Good point on #3. I will l will leave the modifier out and see if it gets noisy.
Noisy? I don't think noise is what you're looking for. Go to a parking lot, drive in a figure eight. If you need some modifier, you'll know quickly. I think I endded up with about a 1/2 bottle with my full synthetic gear oil, but it had no modifier in it.
