Tranny to Tcase Leakage

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Topic author
dissinnick
Posts: 96
Joined: Mon May 07, 2018 12:53 pm

Tranny to Tcase Leakage

Post by dissinnick »

Hi Guys,

As much work as ive done on FSJ's i havent had much experience with Tranny to Tcase mating.

I have a 4l60 with a NP241c pass drop with a clocking ring.

Question:
- is there supposed to be a gasket between T/CR/TC?
- or is the fluid supposed to be blocked by seals on the TC and Tranny?

SJTD
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Re: Tranny to Tcase Leakage

Post by SJTD »

Usually there are seals on the TC and trans and no gasket but Idunno about your trans.
Sic friatur crustulum

'84 GW with Nissan SD33T, early Chev NV4500, 300, narrowed Ford reverse 44, narrowed Ford 60, SOA/reversed shackle in fornt, lowered mount/flipped shackle in rear.
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Yeller
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Re: Tranny to Tcase Leakage

Post by Yeller »

Fairly common issue. With a clocking ring there are a lot of pieces that can make it difficult to seal. However don’t fret. It’s not a terrible job and can be done in a few hours. Unless your feeling strong get a buddy to help the transfer case is 120-130# and needs to be removed along with the clocking ring. Clean up the sealing surfaces. Get a tube of “Rite Stuff” liberally apply to all surfaces that mate to each other and reassemble. The issue is there are some surfaces with very minimal contact so they tend to leak.

However before doing this work make certain that you are not getting fluid coming out of the vent. It would be no fun to go to that work and figure out the fluid Is coming from the vent, often clocked transfercases get overfilled and leak out of the vent, your transfer case needs to be filled by measuring the fluid the fill hole cannot be used for being “full” there should be no more than 3qt-8oz of fluid, more is not better it will froth and push out the vent. On my clocked 241c I only put 3qt in mine.

Gasket sealant:
https://www.amazon.com/Permatex-25228- ... 4913753424
The bus I ride is so short it is a yellow Smart Car full of squirrels, monkeys and clowns.

1970 J2500 Resto Mod
https://www.fsjnetwork.com/forum/viewt ... 12&t=21395

1974 Bronco “Broncno”
https://classicbroncos.com/forums/threa ... st-3411909
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Yeller
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Re: Tranny to Tcase Leakage

Post by Yeller »

FYI there is no seal inside the adapter to seal the transmission fluid away from the mating surface of the transfer case, Jeep is the only manufacturer that does that.
The bus I ride is so short it is a yellow Smart Car full of squirrels, monkeys and clowns.

1970 J2500 Resto Mod
https://www.fsjnetwork.com/forum/viewt ... 12&t=21395

1974 Bronco “Broncno”
https://classicbroncos.com/forums/threa ... st-3411909

SJTD
Posts: 1924
Joined: Tue May 21, 2013 12:02 pm
Location: Lompoc, Sunland or somewhere between

Re: Tranny to Tcase Leakage

Post by SJTD »

So no seal on the transmission shaft?

I'll have to take a look at my NV4500 since I happen to have the Xfer case out. I had used sealant on the interface but I thought of it more to keep junk out. I installed it last century.
Last edited by SJTD on Fri Jul 30, 2021 10:26 pm, edited 1 time in total.
Sic friatur crustulum

'84 GW with Nissan SD33T, early Chev NV4500, 300, narrowed Ford reverse 44, narrowed Ford 60, SOA/reversed shackle in fornt, lowered mount/flipped shackle in rear.
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Yeller
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Re: Tranny to Tcase Leakage

Post by Yeller »

On a 4l60 no, on a nv4500 very likely does.
The bus I ride is so short it is a yellow Smart Car full of squirrels, monkeys and clowns.

1970 J2500 Resto Mod
https://www.fsjnetwork.com/forum/viewt ... 12&t=21395

1974 Bronco “Broncno”
https://classicbroncos.com/forums/threa ... st-3411909

RamJetFSJ
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Re: Tranny to Tcase Leakage

Post by RamJetFSJ »

I have the same problem with my 700r4. I thought it was leaking from the transfer case. I rebuilt the transfer case, and still have the leak. I guess I didn’t seal the adapter to the trans/TC well enough. I thought they both had their own seals.
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Topic author
dissinnick
Posts: 96
Joined: Mon May 07, 2018 12:53 pm

Tranny to Tcase Leakage

Post by dissinnick »

Okay,

So I took the tcase out.

Note: it leaks like a sieve when it’s not running, poor tranny fluid in and within a day there’s a puddle from the tcase to tranny mate.

Ignore the gasket and black gasket maker, that was my last attempt.

Anything look like it’s missing?

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Yeller
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Re: Tranny to Tcase Leakage

Post by Yeller »

Where these bolts are at is likely your culprit, they create a pathway for the leak. Clean all surfaces removing all old sealant and gasket. Liberally use the sealant I referenced above and do not use the paper gasket.
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The bus I ride is so short it is a yellow Smart Car full of squirrels, monkeys and clowns.

1970 J2500 Resto Mod
https://www.fsjnetwork.com/forum/viewt ... 12&t=21395

1974 Bronco “Broncno”
https://classicbroncos.com/forums/threa ... st-3411909

Topic author
dissinnick
Posts: 96
Joined: Mon May 07, 2018 12:53 pm

Re: Tranny to Tcase Leakage

Post by dissinnick »

Thanks for the sanity check Yeller.

I will keep you posted!
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Yeller
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Re: Tranny to Tcase Leakage

Post by Yeller »

Always happy to share my hard learned lessons. Hopefully saves some grief for you or someone else.
The bus I ride is so short it is a yellow Smart Car full of squirrels, monkeys and clowns.

1970 J2500 Resto Mod
https://www.fsjnetwork.com/forum/viewt ... 12&t=21395

1974 Bronco “Broncno”
https://classicbroncos.com/forums/threa ... st-3411909
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