Leaky Transfer Case Output Seal

[darkone98]

So after replacing my toast transfer case with a used one and filled it with 2.5L of 5w30 mobil1, I have noticed the rear output seal leaking. The seal was replaced, and the output shaft bearings do not seem to have any play in them, but still this leak persists, and it is not pump rub. The yoke had a very small groove, barely enough to catch your fingernail on; could this be too far worn?. I can't see it being driveline angles with the lift, as the old transfer case never leaked from the seal. Do they make a speedy-sleeve for the yoke, or would I have to buy a new one? Do they make a slightly tighter I.D. seal or a slightly larger yoke? There is nothing worse that replacing a seal just to have it leak more than the old one.

 

[Andrew]

sounds like just a defective seal honestly

 

[darkone98]

I don't see how, as I never had an output seal leak until I swapped over to this transfer case. It didn't leak in the donor truck, and neither did my original. I cannot see why it would do it now, especially after a new seal which made the leak worse.

 

[THEFERMANATOR]

Mine has seaped just a tiny bit since I swapped it to 5W30. Put in a new seal and it still seaps just a tiny bit.

 

[DAVe3283]

It is quite possible to get a brand new defective seal. I replaced my axle seals because one was weeping. Thought it would be good to do the pair. NOPE. The side that wasn't leaking started leaking badly with the new seal. Returned it, and the 2nd new seal was fine. So yes, it could be a bad seal.

However, since the case didn't leak before you put it in the truck, it would seem that the yoke might be the problem. A scratch you can feel with a fingernail is huge from a sealing standpoint.

If the leak isn't that bad, you can just wait for it to build up a crust, and often the crust stops the leak. My '82 uses this method of sealing on the trans :spit:

 

[hondarider552]

Worn bushing. I've gone through 3 seals

 

[Vrabel]

My bet is output shaft bushing worn

 

[darkone98]

Figured I'd revive this thread with an update. I am having to fill my transfer case every two weeks just to not run it dry. It is definately the bushing, there is a good amount of play in my yoke. I just recieved a new aluminum rear housing that comes with the new bushing, Morse chain, and also a complete bearing/seal rebuild kit as I have run this case down to 1/2 a liter of oil before. It shifts on the fly seamlessly, and there are no irregular sounds coming from it. I want to replace the fork pads, but I don't know if it has the updated fork/slider, and I cannot afford to tear it down to find they are non-serviceable and have to wait on parts as this is my work truck. This is a stock transfer case I swapped in from at least a 2003. Would this case have the changeable fork pads? Or should mine be ok as long as it is shifting perfectly?

 

[DBUSHLB7]

I had to replace the bushing, seal, and slip yolk to completely stop my leak. No leaky no mo

 

[darkone98]

That is my plan, I have a nickel plated 1410 yoke on it's way as well. I was wondering if my fork pads would still be good after running the case down to half a liter, It still shifts and operates perfectly, with no unusual noises.

 

[pullsanything]

I would do a pump rub kit while you are at it also.

 

[darkone98]

I have the aluminum rear case half, a pump rub kit won't fit, and isn't necessary as it is the same material as the pump.

 

[pullsanything]

I thought they were all aluminum.....

 

[Evan@InglewoodTrans]

I thought they were all aluminum.....

They are magnesium.

 

[pullsanything]

They are magnesium.

Ahhh, I understand.

 

[Mark P]

I changed my transfer case rear output shaft seal 3 times on my 08 Silverado and each time the leak seemed to get worse. Every time I drove with the windows open or parked in my garage, it smelled like the truck was about to catch fire from the oil burning off the exhaust. I checked the bushing and transfer case housing, and everything was fine. After pulling out most of my little remaining hair out, I was able to find a post on some other site from someone with the same problem (the leak, not the receding hairline) who discovered there is a pressed in plug at the end of the yoke. This plug loosens over time and oil can leak out, which is then flung off the driveshaft and making it very hard to find the point of origin of the leak. All I did to stop the leak is put smear some RTV over the plug. I didn't even need to pull the driveshaft for the fourth time. Damn I love the internet?

 

[minerigger]

I'm going to revive this and pray some bright minds read it. I have put 4 output seals in transfer case. This last go round, last May, I put new output seal, new ujoints, and a new output bushing. Put 2 quarts of 5w-30 Mobil 1 synthetic oil in and went on my way. Now the stupid thing leaks even worse.

I installed the bushing with the small drainage hole over the rib that would allow the oil to trickle back into the transfer case. I don't know that the slip yoke is nickle plated as it's rusted on the shaft portion where it is open to the elements. I did notice that the yoke seems to ride more towards the bottom, that or the seal is worn odd. I tried to get a picture of what I'm seeing so hopefully it helps.

So all I can figure at this point is a new 1410 nickle plated yoke along with new output seal is all that's going to fix it. I'll attach some pics and see if anyone has any ideas. I'm really open to ideas and help. Thanks all

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[minerigger]

Here are some pictures of the headache.

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[minerigger]

I did read a few old threads where Mike said it was possible to modify the spring in the seal but " you better know what your doing" I believe is what he said. Anyways I'm all ears for anyone's input, ideas, things to check. I'm getting tired of small leaks from the transfer case and other small ones from the transmission.

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[minerigger]

Mmm cough! Need some duramax veteran wisdom and input.

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