About to change my differential oils at around 3k miles. So, like gasoline, oils come in comparable weights to each other (is 80W-90 of one brand better or worse than 80W-90 of another?), like gas comes in same basic octanes. Unless you're European, then you get RONs and some other kind of RONs, all very confusing. Anyway, the only way to really know is to run scientific, measurable tests on differentials with different brands of diff oils. I think what might matter in the differential oil case too is synthetic / non-synthetic (former I think lasts longer), and then the additives packaged in each brand's oil, but I don't know if any testing has been done that could show benefits of 'premium' gear oils over other brands.
I watched the Motor Oil Geek, this episode: can premium gas reduce wear on your engine. I now use Shell when I'm north, Chevron when I'm south, premiums, because I thought gas was gas, but not so and this talk convinced me. It's not the gas base itself that matters, but the additives you get in the tanker truck based on what gas station brand that truck is making its next delivery to that makes a huge difference apparently, according to Lake Speed Jr., and he has the receipts (from a German study on premium versus basic gas).
View: https://www.youtube.com/watch?v=DAmEGI7xvBw
I will go with the Fuchs oils as INEOS specifies for this diff oil change, though might go with the synthetic version (the "MC" version, but I think that's for the transfer case, next up for an oil change), and change to a better brand based on their additive package when I can find that evidence.
What diff oil did you decide to go with?
/s.
