Transfer Case Shaft Leaking-Help!

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renovate7
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Transfer Case Shaft Leaking-Help!

Post by renovate7 » Sun May 21, 2017 12:24 pm

I pulled the transfer case out of my DUKW and replaced all the seals and gaskets. It is now leaking, rather badly, between the lower yokes and splined output shafts they go on. These are below the gear oil level and so are immersed in the oil all the time, unlike a differential. I tried disconnecting the drive shafts, pulling the yoke nuts, cleaning that area with carb cleaner, applying a whole bunch of permatex #2 and reinstalling the yoke nuts but still have the leak. What is the proper procedure for sealing the yokes to splined shafts they go on? When I pulled them down there was no washer or any amount of sealant I noticed on the yokes/shafts. My TM9-802 doesn't cover this. Thanks for The Boards help.


mudflap
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Re: Transfer Case Shaft Leaking-Help!

Post by mudflap » Wed May 31, 2017 9:26 am

Hello renovate7,

Are you 100% sure that the source of the leak is the splined interface between the shaft and the flange? If so, did you notice any clearance between the flange and shaft when you had the flanges off? Was the fit kind of sloppy, or did they go on tightly?

When I had mine off a few years ago to replace the seals, the fit on one of them was pretty loose. On disassembly, I noticed that the nut was very only finger tight, even though the cotter pin was still in place. Not sure if perhaps the last time the TC was serviced, that nut was not torqued properly? On reassembly, there was noticeable rotational clearance between the flange and the shaft – such that with the flange fully seated, you could feel significant movement between the flange and shaft when you tried to rotate the flange.

If this is the condition you have, I doubt a soft sealer like Permatex #2 will have the strength required to withstand the pressure between the splines.

Luckily, there are a number of products designed for this type of repair. I used a two part Loctite product called Superior Metal, designed specifically for spline and shaft repair. It is referenced in the attached application guide.

http://www.loctite.sg/sea/content_data/ ... _Guide.pdf

It worked very well, and that flange is still tight several years and many miles later. Just make sure you follow the directions carefully with respect to using a silicone “release lubricant”. Otherwise, if you ever try to remove that flange again in the future, you will have a difficult time.

I have also noticed that Loctite now has a product for this application called 660. It looks promising, but I have not had any experience with it.

Another option would be a new flange, if you can locate one.

For applications where the splines fit snugly, and I just need something to fill in any gaps, I use this RTV sealer:

https://www.permatex.com/products/gaske ... ket-maker/

They claim it resists the additives (friction modifiers, etc.) in gear oil better than standard sealers.

Best Regard…

mudflap
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Re: Transfer Case Shaft Leaking-Help!

Post by mudflap » Wed May 31, 2017 6:26 pm

Was also just thinking that you may want to check the breather, too. Although, not having been into my TC deeper than the seals, I'm not 100% sure exactly where it is located.

The parts manual lists a PN for it, but does not actually show it in the exploded diagram. Likewise for TM10-1501, TM10-1563, and TM9-1801. In the text, they all tell you to clean it, but it does not show up in the exploded views. Only on some pics, can you see what looks to be a breather on the rear upper bearing retainer.

Would be interested if anyone has any additional information on this part.

Best Regards.

Peterdodge6volt
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Re: Transfer Case Shaft Leaking-Help!

Post by Peterdodge6volt » Sat Sep 16, 2017 11:19 pm

Did you check the yoke where it's sits through the seals, the yoke usually get worn out where the seals is touching, that's where it will start leaking.
Mine already start leaking through the yoke seals as its worn out.

Peter


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