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WTF! Rear diff rusted and leaking?!

Discussion in '3rd Gen 4Runners (1996-2002)' started by Akjackson, May 29, 2018.

  1. May 29, 2018 at 10:02 AM
    #1
    Akjackson

    Akjackson [OP] New Member

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    175000 miles. Good shape. Runs strong. Hardly had to do any maintenance in last 80,000 miles. Just changed timing belt. Crawled under truck to inspect the other day and my rear diff was covered in oil on the backside. I popped the fill plug off and was only about a 1/4 q low so I topped it off. Wasn’t really sure where it could be leaking from. The whole front side was dry. I then started to inspect more and there was a lot of rust built up and am assuming it’s rotting out!!? I would think this would be a large hunk of metal that would be the last place to rot out. I have a 89 yota pickup that looks 100 times better with almost 50,000 miles mor plus 13 years. I don’t know what to do? The rear brake backer plates are rusting out as well.
     
  2. Jun 2, 2018 at 7:07 PM
    #2
    2016 4Runner SR5

    2016 4Runner SR5 CONTACT ME FOR CORNFED LIFT SPACERS 631-202-8245

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    #ChrisCornfed
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    Find another axle at a scrap yard and swap it in. This is why you should inspect everything under there with every oil change. How often do you change your engine oil, gear oil, transmission fluid, transfer case, and just do a general look over?
     
  3. Jun 2, 2018 at 9:21 PM
    #3
    xdelmar

    xdelmar New Member

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    Currently San Felipe, Baja.
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    I want to travel and camp and will do Mod's necessary to do this with a 4runner.
    Interesting. But I'm from the old school.
     
  4. Jun 2, 2018 at 9:44 PM
    #4
    Akjackson

    Akjackson [OP] New Member

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    I do my own oil changes ever fall. I leave Alaska for three months in the winter. My wife is the primary driver and puts about 3000 on in the summer. I look under there prob once a summer but never in depth. Last gear oil change at 120000. Was going to do it again in a few weeks and looked under there the other day and saw oil dripping. Def never saw the oil before. Didn’t look too terribly rusted and to be honest never thought if my diff rusting out. I would think it would be there way after everything else was long gone. My 89 yota pickup has hardly any rust on the diff housing and is not garaged. I don’t think this is something that should happen. I do however regret not staying more on top of the rust. But now I will and have a lot of work cut out for me. The rear brake backer/dust plates are rotting out as well. I feel like this has all happened relatively recent due to the fact I took it to the shop last year and just had the di a full undercarriage inspection and change out the rear shocks. I would have thought they might have mention the need for cleaning things up or given me a heads up? Frustrating. Trying to find a scrap yard in Alaska with a rear axle assembly will be near impossible. Especially one that won’t be trashed. Thanks for the input.
     
  5. Jun 3, 2018 at 4:38 AM
    #5
    2016 4Runner SR5

    2016 4Runner SR5 CONTACT ME FOR CORNFED LIFT SPACERS 631-202-8245

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    #ChrisCornfed
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    Not sure what you're getting at here lol? Old school or new school, housing is still rotted. What's your "old school" solution?
     
  6. Jun 3, 2018 at 4:40 AM
    #6
    2016 4Runner SR5

    2016 4Runner SR5 CONTACT ME FOR CORNFED LIFT SPACERS 631-202-8245

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    #ChrisCornfed
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    You should be under there more often for sure especially in such a harsh environment. When I bought my 4R brand new, I was under it within a week greasing everything and painting literally everything. I'm under it 3-4 times a year with a can of black spray paint coating everything in sight. May be overkill but it'll never rust and if something does rust i'll catch it right away. Where exactly is the rot? There are other backyard fixes but they have to be done "properly" to avoid causing other problems.
     

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