FT Diff - Check your nuts

Discussion in '80-Series Tech' started by landtank, Sep 14, 2018.

  1. landtank

    landtank SILVER Star

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    Quite a few times I've come across front diffs that leaked from gasket between the axle housing and Diff carrier. It's almost always loose nuts. However while out at Cruise Moab on my final trail run @cruiserdan spotted a large oil spot moments after we parked for lunch and sure enough the nuts were quite loose and the gasket was torn. Luckily we were near the end of the trail and while I had a 36 hour drive home I'm part time so not a problem. Dan mentioned that Toyota at some point eliminated the lock washer for a flat one and that was likely the issue.

    So I went on the hunt for better nuts and found some that I like. They are a JIS serrated flange nut, class 10.9 and zinc plated.

    Today I tore apart the axle to replace the gasket and install the new nuts. As it turns out I did have lock washers they simple didn't do the job for me.

    Attached are the before and after pics of the diff along with one of the nuts I used.

    It takes 10 for an open diff. This is just the front diff and I'll get some for the rear and swap them out as well.
    20180914_153246.jpg 20180914_160134.jpg 20180914_160126.jpg
     
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  2. Tools R Us

    Tools R Us

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    That should be on the occasional torque check list. If the gasket is ditched and the diff is installed with Permatex Gray, the nuts almost never come loose and leaks are greatly reduced.
     
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  3. landtank

    landtank SILVER Star

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    I had previously use FPIG on the failed gasket. I'll check these before my next trip but the truck gets very little use.

    My rear diff is fine and I just ordered nuts for that and will change them out 1 at a time so no need to tear in and deal with the gasket as of yet.
     
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  4. nukegoat

    nukegoat

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    Might as well check ring gear bolts while you're at it since apparently those come loose randomly on their own too
     
  5. chap79

    chap79 Wheel. Break. Fix. Repeat. SILVER Star

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    I’ve had this happen a few times too. Used blue loctite last time I tore into it and haven’t had the issue return :meh:
     
  6. inkpot

    inkpot SILVER Star

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    Probably just a rumor? :doh:
     
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  7. chap79

    chap79 Wheel. Break. Fix. Repeat. SILVER Star

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    They don’t come loose when you don’t bounce them off rocks. IME...
     
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  8. Cruiserdrew

    Cruiserdrew On the way there SILVER Star

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    It's only the front 80 diff that has this problem, but it's very, very common. I think the 8mm studs just are not up to the task. Or maybe there's some strange torque forces with the high pinion diff.

    Anyway, check them every oil change, and I doubt you'll have further problems. And I got rid of the paper gasket up front too and went to the FPIG.
     
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  9. mudgudgeon

    mudgudgeon

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    I replaced all the studs and nuts on my HZJ105 with 10mm studs when I had the diff carrier out.

    Fairly common issue. I've used paper gaskets and FIPG and had leaks and loose nuts with both
     
  10. amay3

    amay3

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    Hey Richard,
    Many thanks for this post. Where did you source the JIS flange nuts?
     
  11. landtank

    landtank SILVER Star

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    I talked with Joey at wits-end and he's going to stock them. it will be cheaper then buying as i did.
     
  12. davework

    davework Cruiser Hardware: OverlandMetric.com Supporting Vendor

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    For JIS Flange Nuts with serrations, the best place I’ve found for them is BelMetric.com. Reasonable shipping on small qtys. If Joey will stock them, even better though.
     
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  13. davework

    davework Cruiser Hardware: OverlandMetric.com Supporting Vendor

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  14. landtank

    landtank SILVER Star

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  15. NLXTACY

    NLXTACY Wits' End Supporting Vendor

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    ^ this
     
  16. 80t0ylc

    80t0ylc Hill & Gully Rider

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    Thinking about Nylock nuts, but they're temp limited.

    "THERMAL PROPERTIES Most nylon insert locknuts are manufactured from Zytel 101 which has an effective temperature range up to 250 ° F. Zytel 103 has a higher effective range to 350 ° F and can be special ordered for your higher heat applications."

    Would the Zytel 103 work or does the normal diff temps exceed that? Trying to remember what I've read with my laser thermometer when checking heat readings, before...:bang: ...damn dementia...lol
     
  17. Tools R Us

    Tools R Us

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    The active part is, not using the gasket.
     
  18. Tools R Us

    Tools R Us

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    Doubt that is a problem here, even the diff drain plug ring is virgin, never been kissed.
     
    Last edited: Sep 15, 2018 at 1:07 PM
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  19. davework

    davework Cruiser Hardware: OverlandMetric.com Supporting Vendor

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    Agree. But how often are diff covers pulled? Wouldn’t it be better to have a locknut rather than not?
     
  20. LandCruiserPhil

    LandCruiserPhil Peter Pan Syndrome Supporting Vendor

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    Factory locked diffs uses more hardware than non locked.

    I had nothing to match the yellow zinc so I used clear zinc:flipoff2:

    Before

    [​IMG]

    What is needed for factory locked diffs

    [​IMG]

    Results :princess:

    [​IMG]
     
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