Once again Im overthinking stuff. I need a sanity check. Im replacing the gear oil in my 8.2 limited slip diff.... I bought AC Delco #89021669 80w-90 GL-5 Hypoid. Says its for use in conventional type axles. Naturally not limited slip. So I bought the AC Delco LSD additive in addition. In the past, Ive always used Valvoline 80W-90 "Limited Slip" GL-5 gear oil and the additive in addition. But the limited slip oil just has the additive built in right? So is it a waste adding additive to the LSD gear oil? Is it six 0f one and half a dozen of the other? Does it really matter?