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Rear Diff Leak

Discussion in '2nd Gen. Tacomas (2005-2015)' started by saj102719, Nov 22, 2021.

  1. Nov 22, 2021 at 9:41 PM
    #1
    saj102719

    saj102719 [OP] Member

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    A few days ago I changed the oil in my front diff, rear diff and transfer case on my 08 Tacoma. Before changing the rear diff, I had noticed a slight leak at the drain plug and some oil pooling under the truck. The rear diff was very dirty/grimy as well. So when I changed the oil in the rear diff, I put in a new drain plug and crush washer and torqued to specs. It has been a week or so since I changed the oil and while there isn’t a large amount of oil leaking out, after the truck sits cold for a while, a small amount of oil will still slowly drip from the drain plug. Any thoughts on what to do? Thank you!

    C9819727-93EB-499A-A77A-E8391CEEE700.jpg
     
  2. Nov 22, 2021 at 10:53 PM
    #2
    TnShooter

    TnShooter The TacomaWorld Stray

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    There are a few of options.

    Some require draining the diff once again.
    At least one doesn’t. And that one is surely going to bring on the hate.
    But hey, it’s an option. Maybe not the best one, but a last one maybe? (It’s option 4 below)

    1. Try to see if you can snug it up a little. Don’t crank on it too hard.
    You don’t want to strip it. But maybe it just needs to be cranked down a smidge more?

    2. Remove plug and inspect mating surfaces.
    Make sure there isn’t an old gasket stuck to the diff.
    Clean surfaces good. Replace with new gasket washer.
    Tighten it until you think it’s good and tight, then check it with a TQ wrench.


    3. Use Thread Sealer
    https://www.permatex.com/products/t...nts/permatex-high-temperature-thread-sealant/

    4. Use an RTV gasket maker and “fill” the area around the drain plug.
    Yes, this is absolutely a “Shoddy Fix” and is not at all considered right or correct.
    But there have been guys fix their timing cover leaks this way. Mostly because it a big job, and smearing RTV is much easier.
     
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  3. Nov 22, 2021 at 10:54 PM
    #3
    Superdave1.0

    Superdave1.0 Grandma Dave

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    Pull fill plug
    Top off
    Replace crush washer ($1)

    Edit: Is the drain plug leaking or the fill plug?
     
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  4. Nov 22, 2021 at 10:56 PM
    #4
    TnShooter

    TnShooter The TacomaWorld Stray

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    That’s also an option.
    Do nothing and add fluid as needed.
    I’ve done it myself. :eek:
     
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  5. Nov 22, 2021 at 11:26 PM
    #5
    Shadowhunter

    Shadowhunter Well-Known Member

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    Just throwing it out there if it’s not the plugs. It could be the pinion seal and it’s working back there when you driving.
     
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  6. Nov 22, 2021 at 11:43 PM
    #6
    TacoTuesday1

    TacoTuesday1 Well-Known Member

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    double check torque spec
    clean with brakleen and re-evaluate
    these housings can crack and leak but usually look in way worse shape when they do that
     
    Nick_Taco likes this.
  7. Nov 23, 2021 at 1:27 AM
    #7
    TruckGuy63

    TruckGuy63 Well-Known Member

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    The threads are leaking. Like a plumbing fixture. Remove the plug and put Teflon tape or thread sealant flip crush washer over or replace tighten and let dry over night if using thread sealant
    Leak will stop. Happens all the time
     
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  8. Nov 23, 2021 at 1:45 AM
    #8
    burrito782

    burrito782 Shit Throwing Ape

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    He said drain plug and if you look at his pic you can see the oil dripping from the low point of the drain plug boss.
     
  9. Nov 23, 2021 at 1:56 AM
    #9
    burrito782

    burrito782 Shit Throwing Ape

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    OP, these fellas have provided some good advice here for consideration.

    Touching on TnShooter's #2 option, the fact that you've changed both the plug and washer would make me question the integrity of the mating surface of the diff drain plug boss, so be sure nothing is dorked up with that. Also, as @TnShooter alluded to with option #4 being a shoddy fix, I can't help but think of option #3 the same as well and if given the pick between those two I'm probably going with option #4 over #3. To me, the seal is suppose to be happening at the mating faces, not the threads, so I'd be wanting to apply the BAND-AID fix in that proximity. Either way, both would work and as they say, "desperate times call for desperate measures."
     
    Last edited: Nov 23, 2021
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  10. Nov 23, 2021 at 2:02 AM
    #10
    burrito782

    burrito782 Shit Throwing Ape

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    These are not NPT (pipe) threads that form a seal at the threads, they are straight threads and provide no seal.
     
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  11. Nov 23, 2021 at 2:37 AM
    #11
    TruckGuy63

    TruckGuy63 Well-Known Member

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    I didn’t realize it was the drain plug
    It looked like the fill plug was leaking in the pic.
    Even though the treads are not sealing this same thing happened to my on one of my other trucks a Nissan Frontier . I cleaned the surface of the plug , cleaned the surface of where it mates at the diff and put a new crush washer and it still leaked. Although my issue was on the fill plug only. My solution was thread sealant and letting it dry over night .
     
  12. Nov 23, 2021 at 2:47 AM
    #12
    Hook78

    Hook78 Well-Known Member

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    Given how little fluid is in the rear diff and the ease of access, for me it’s a no-brainer what I’d do. Buy a new plug and crush washer. Drain the diff, wipe the drain hole dry and inspect it and the plug closely with a flashlight. Mating surfaces and threads. See if there’s a doubled up crush washer. Hope that you find something obvious. Install new drain plug and washer and refill. Check the torque a few times. Maybe your wrench is out of calibration.
     
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  13. Nov 23, 2021 at 3:06 AM
    #13
    burrito782

    burrito782 Shit Throwing Ape

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    Yeah I hear ya. Gotta do, what you gotta do. Sounds like you went with option #3 from TnShooter's post. Plus, sometimes there comes a point with leaks where you're just over it and ready to move the F on with life...so out comes the sealant. :laugh:
     
  14. Nov 23, 2021 at 5:18 AM
    #14
    saj102719

    saj102719 [OP] Member

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    Thank you for the input! This is all very helpful. I did already try torquing the drain plug down again and it didn’t seem to help and I’m 99% sure the old gasket wasn’t left on. I cleaned everything off really good and inspected closely before putting the plug back in. I’m curious to try the thread sealer and see if that helps. I’m going to replace the crush washer again too but I did have a question about that to make sure I installed it right the first time. I put the flat side facing the bolt head (curved side facing the drain hole). Is this correct? Thank you all again for your help! I don’t know what I’d do without this community.
     
  15. Nov 23, 2021 at 6:14 AM
    #15
    Hook78

    Hook78 Well-Known Member

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    Flat side facing the plug, yep.
     
    Last edited: Nov 23, 2021
  16. Nov 23, 2021 at 6:18 AM
    #16
    Texoma

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    A bunch a cool stickers, a bada ass MetalMiller Tx Longhorns grill emblem painted Hemi Orange, JBA long tube headers with o2 sims, Diff breather mod, Red LED interior lights, Fancy head unit that plays ipod n movies, Also DIY install factory stuff like, factory cruise control, factory intermittent wipers, OME nitro struts with 886x springs and toy tec top plate, JBA high caster UCA's for better alignmnet and dey beefier too, Old Man Emu Dakar leaf springs in da rear with the gear, U bolt flipper, Ivan Stewart TRD rims with 33" K Bro 2's, some bad ass weather tech floor liners so I don't muck up my interior, an ATO shackle flipper for mo travel in da rear wit the gear, also super shiny Fox 2.0 shocks back there too, all sorts of steal armor for bouncing off of the rocks like demello sliders, AP front skid, trans skid, n transfer skid, demello gas tank skid, and a tough as nails ARB bumper with warn 8k winch, I'm sure there's more
    Sometimes an old crush washer gets stuck on the diff housing and you'll need to pry it off with a screw driver. It would create a leak similar to this.
     
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  17. Nov 23, 2021 at 7:29 AM
    #17
    Roberto123

    Roberto123 Well-Known Member

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    Had same happen on a Sequoia I had. Somehow, when the plug was removed I nicked the mating surface on the diff. side. I could run my finger on the surface and feel the knick, small, sharp. I smoothed the surface with a fine file. I am not sure if this procedure is recommended or not, but it worked.

    Initially, I thought the issue was the new crush washer or plug, I ran the truck for a week waiting for the new washer and plug. When I drained the diff after a week I planned to reuse the fluid. The fluid came out so nasty again that I replaced it.

    Good luck!
     
  18. Nov 23, 2021 at 7:41 AM
    #18
    Knute

    Knute Well-Known Member

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    OP.....as a thought.....

    You could try a fine wet/dry sandpaper to clean/polish the gasket surface. Just making sure all is clean and without nicks or burrs.
     
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  19. Nov 23, 2021 at 6:28 PM
    #19
    winkel

    winkel Well-Known Member

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    Teflon tape.
     
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  20. Dec 7, 2021 at 7:24 PM
    #20
    saj102719

    saj102719 [OP] Member

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    Well, I tried most of these suggestions (new washer, new plug, cleaned/lightly sanded the mating surface, thread sealant) and there is still a leak.

    Would you recommend I try tightening the nuts on the diff? I’ve read a few threads of guys causing more issues by doing this so that’s why I’m asking. If I researched correctly, I believe my 08 V6 off road should call for 18 ft lbs on the rear diff nuts.

    If you have any other suggestions, please let me know. Thanks!
     

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