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  • why does diff oil turn black?

    From Woong Sinh@21:1/5 to All on Fri Feb 24 15:06:00 2023
    I change diff oil after a few years. It is black, and the stuff I put in
    is a nice clear blue color.
    It is not getting combustion blowby as in engine oil.
    BTW is rear drive, not limited slip. And is not one of those V8 cars
    with stage 3 tune, 500 kW on the dyno, so shouldn't be overheating.

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  • From Scott Dorsey@21:1/5 to [email protected] on Fri Feb 24 11:55:45 2023
    Woong Sinh <[email protected]> wrote:
    I change diff oil after a few years. It is black, and the stuff I put in
    is a nice clear blue color.
    It is not getting combustion blowby as in engine oil.
    BTW is rear drive, not limited slip. And is not one of those V8 cars
    with stage 3 tune, 500 kW on the dyno, so shouldn't be overheating.

    It's all metal oxides and sulfides building up in solution. Feel those
    gears after 200,000 miles and notice how sharp the tips are and thin the
    teeth are? The metal that used to be on there is now in solution in the
    fluid.
    --scott
    --
    "C'est un Nagra. C'est suisse, et tres, tres precis."

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