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T86aa Case Front Bearing Retainer Questions

Discussion in 'Early CJ5 and CJ6 Tech' started by truckee4x4, Jun 30, 2020 at 2:00 PM.

  1. Jun 30, 2020 at 2:00 PM
    truckee4x4

    truckee4x4 Member 2020 Sponsor 2019 Sponsor

    Truckee CA
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    I’m trying to leak proof my T86 case around the front as there was oil in the bottom of the adapter cavity during tear down.

    I took off the front bearing retainer to redo the seals and the last person who rebuilt this transmission did not use a paper gasket, they used RTV, which was pretty deteriorated. They siliconed the oil return hole shut as they used a bearing that is sealed on the front side. The bearing and the seal on the retainer are in really good shape so I am not going to change them.

    I don’t have a lot of experience working with RTV so I wanted to ask a question. Since I have this apart should I pull the old plug RTV dab out of the oil return hole and put in some new RTV?

    I have the paper gasket from the crown kit, is it worth putting this on with sealant, or should I just RTV the whole thing again?

    and lastly, the button head Allen screws that hold the retainer onto the case had crush washers behind the bolt heads that were staked into the side of the heads. Should I replace these with new ones or use internal tooth lock washers and locktite 243? The crown kit has paper bolt gaskets but I don’t think those are a good idea.

    love to get the thoughts of the experts who e dealt with these issues before. Thx.

    8C8E79C6-8717-4B6B-8224-68C5BFECE329.jpeg FC3CACBD-393B-48AA-A8CC-9214C83F761A.jpeg
     
  2. Jun 30, 2020 at 2:22 PM
    Walt Couch

    Walt Couch sidehill Cordele, Ga. 2020 Sponsor 2019 Sponsor

    cordele, Ga.
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    In your upper pict you will see a hole below the threaded hole to the far left. That is a drain return that aligns with a cast in channel in the retainer. The three mounting holes are equal distant meaning three different mountings but only one is correct. Since you have a vent in the D-18 and the two units share oil, you don't build any pressure in the tranny. A little black RTV won't hurt on the paper gasket. Should be a felt seal in the retainer.
     
  3. Jun 30, 2020 at 3:14 PM
    truckee4x4

    truckee4x4 Member 2020 Sponsor 2019 Sponsor

    Truckee CA
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    this is the hole that’s plugged with RTV. I suspect because the front of the bearing is sealed the last person through the process didn’t think oil needed to get out here. Does that make sense to re-plug?

    And there was no felt seal either.
     
  4. Jun 30, 2020 at 6:06 PM
    Twin2

    Twin2 not him 2020 Sponsor 2019 Sponsor

    Virginia Beach, VA
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    sealed bearing or not . oil will seep on outside of bearing
    and I see a shiny ring on shaft . no seal :confused:
     
  5. Jun 30, 2020 at 6:13 PM
    truckee4x4

    truckee4x4 Member 2020 Sponsor 2019 Sponsor

    Truckee CA
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    Isn’t the ring from the rubber lip on the seal that’s pressed into the retainer?
    894C4008-E2C4-425F-A0BF-40B81E2059C3.jpeg

    Shown here with a couple dabs of transmission assembly lube on it to keep the spring in place.

    How important is putting it back together with a felt seal since I have a sealed bearing?
     
    Last edited: Jun 30, 2020 at 6:51 PM
  6. Jun 30, 2020 at 7:15 PM
    nickmil

    nickmil In mothballs.

    Happy Valley, OR
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    Don’t use the felt seal, it will cause binding and other issue on the retainers with a seal. Some transmissions like T-90’s and some T-86’s didn’t use a pressed in seal so used the felt instead.
    The washers under the bearing retainer bolts are actually seals to prevent leaks past the bolts. A little dab of rtv under the bolt heads and on the threads help minimize leaks. Some copper washers help too if you are so inclined.

    I would not plug up the oil return hold despite using a sealed bearing. Unnecessary if the bearing retainer and seal are installed and working properly and I like the oil to drain back in the transmission if any does work past the bearing

    You want to use the gasket on the front bearing retainer. It acts as a shim/spacer and I’ve seen many bearing retainers cracked because of leaving it out. I would use a very thin coat of The Right Stuff or RTV Ultra Black on both sides of the gasket.
     
    Walt Couch and truckee4x4 like this.
  7. Jul 1, 2020 at 10:23 AM
    truckee4x4

    truckee4x4 Member 2020 Sponsor 2019 Sponsor

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    Thanks @nickmil. I've been using Super 300 on cut gasktes during my rebuild - is that better/worse/same as RTV or TRS? Also, do you recommend any type of dressing between the surfaces of the transmission and transmission adapter?
     
  8. Jul 1, 2020 at 1:57 PM
    nickmil

    nickmil In mothballs.

    Happy Valley, OR
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    The 300 works ok but I’ve had it harden on me before. It can be a pain to remove down the road too and it’s messy. But it does work. Shouldn’t need anything on the adapter if the front bearing retainer is sealed properly. I would add some sealer to the cluster shaft bore to keep seals from happening there. I’d recommend a gasket between the transmission and transfer case.
     
  9. Jul 1, 2020 at 3:11 PM
    truckee4x4

    truckee4x4 Member 2020 Sponsor 2019 Sponsor

    Truckee CA
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    I mistyped - I've been using HighTack sealant on the cut paper gaskets and then Super 300 (or Loctite 242/3) on bolt threads.
     

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