I’m doing a drain and fill on my rear differential - 2002 4.6is. A friend has a bucnch of fresh, still sealed BG 75w 140 GL5 that he isn’t going to use and wants to give me. The specs I've seen call for 75w 90, but I can’t see any reason not to use the BG. They are both 75w, so they should both lubricate the same on the cold end of the spectrum, which to me is the most important. The 140 should just give more protection when it’s hot. Or am I missing something here about gear oil?

Any reason not to use it? If it’s a bad idea in the X5, I’ll just put it in the Tacoma. It will take anything :-).

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2002 e53 X5 4.6is Estroil blue/ Black interior (Build Date 04/02)