Changing Rear-end Fluid.

Discussion in '1996 - 2004 SN95 Mustang -General/Talk-' started by stlboarder, Dec 21, 2003.


  1. stlboarder

    stlboarder Founding Member

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    I'm going to change the fluid in my 7.5" rear-end in a couple days. I don't think it was ever done. Should I use friction modifier? What gear oil do you recommend? I was thinking the mobile 1. What weight?
    #1
  2. BABstangV6

    BABstangV6 Smater than the average bear!

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    Have u put in a t-lock and gears?
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  3. stlboarder

    stlboarder Founding Member

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    nope... thats why I'm asking. Because I know t-loks need it. I wasn't sure about these crappy open diffs.
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  4. BABstangV6

    BABstangV6 Smater than the average bear!

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    Ford should be able to tell you what weight. I forget what i put in mine. sorry, I am sure someone around here knows
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  5. marvinmycat

    marvinmycat Founding Member

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    Hypoid Gear Lubricant SAE 80 or 90.

    If differential is a Trac-Lok limited slip-unit, use 4 oz. of Ford Friction Modifier C8AZ-19B546-A or equivalent special limited-slip additive w/ the lubricant.
    #5
  6. stlboarder

    stlboarder Founding Member

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    What does everyone else run in their rearend?
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  7. marvinmycat

    marvinmycat Founding Member

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    Sometimes a little KY or even Desitine or Preperation-H.

    Sorry, I couldn't resist! :D
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  8. stlboarder

    stlboarder Founding Member

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    Oh, I was waiting for it. But seriously what does everyone else use?
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  9. stlboarder

    stlboarder Founding Member

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  10. hiattwl

    hiattwl New Member

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    I used lucas oil when I swapped my gears, and you can also try red line, but just get something good, don't spend like 99 cents on a quart, be sure to buy something nice, they're all pretty good for stock rear ends, you don't need anything special if you havn't done much to it.

    Wayne
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  11. stlboarder

    stlboarder Founding Member

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    So the Mobile1 oil is fine?
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  12. hiattwl

    hiattwl New Member

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  13. CarlsV6

    CarlsV6 Founding Member

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    I use good ole penzoil gear oil (sae 80) for open diffs.
    #13
  14. stlboarder

    stlboarder Founding Member

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    why 80 and not 90?
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  15. stlboarder

    stlboarder Founding Member

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  16. hiattwl

    hiattwl New Member

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    It's more of a preference, they're both good, and either way you can't lose. You really don't need to use anything special as long as you're still stock, and then, it doesnt matter much because you're not really a circuit racer or depending on your rear end to hold up to 110+mph constantly, just use something that's mid-priced and you'll be happy.

    Wayne
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  17. stlboarder

    stlboarder Founding Member

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    Correct me if I'm wrong. But 90 weight is better at higher speeds than 80 weight. As far as protecting the parts. And when I was at the parts store a lot of the oils were like 75w- 90 and stuff like that. Should I just look for a 90w.
    #17
  18. aznzebra

    aznzebra New Member

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    If you have no posi
    do not use friction modifier.

    the manual for our cars tells you what quantity of 10w90 you should be putting in. i forgot the exact amount required, so i cannot tell you.

    good idea to wear rubber gloves. there is a chemical agent in that lubricant potentially dangerous to your skin.
    #18
  19. stlboarder

    stlboarder Founding Member

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    It says to put in like 3.3 quarts. And what will happen to my skin? I've already drained the old oil without gloves. I haven't melted yet. :D
    #19
  20. aznzebra

    aznzebra New Member

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    I forgot what the chemical was called, but it has been known to give a small risk of cancer with extended exposure
    #20

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