Mine has worked great without the modifier for over 60,000 miles now. If I add it to make someone happy, it would probably be too much and I would lose my LSD. I'm past my warranty and even if I wasn't, I would like to see them send the used lube off and have an analysis done on it and prove it wasn't used. Before I changed my lube, I had a slight shudder on turns. Since I went to synthetic lube WITHOUT THE MODIFIER, I have no shudder and the LSD works like it is supposed to. I had exact same situation in my 98 before I went to synthetics. It all depends on the brand you use whether you need it or not.