Transfer case leak or worse ?? M1008

[Starlight]

Hello all. Put my girl away for the winter and noticed a leak where transfer case buts up to support. I also noticed what looked like old permatex or the like hanging down. Is this a seal that's let go on transfer case ? Fluid level is where it should be on transmission. In the pics I have sprayer all down with brake cleaner to find out leak location. That's why you don't see ATF all over mont, etc.

 

[Tinstar]

West Palm Beach, Florida has a Winter?!

If it sits a lot the seals suffer.

 

[Chaski]

So there is no seal on the output shaft of the transmission. The ATF from the transmission goes into the cavity in the adapter. If the gasket surface from the adapter to the transfer case or the adapter to the transmission is leaking it will be ATF from the transmission. A little oil can make a big mess, so it wouldn't surprise me if you didn't notice a drop in oil level.

The transfer case has a seal on the input shaft so it's ATF won't co-mingle with the transmission fluid.

Now personally I have held a cracked adapter in my hands that came out of an M1008. The adapters can and will crack. Others have also broken transmission cases. I'm not saying that is the cause of your leak but it may be. There is some debate on the forum about the transfer case support rods that go from the case to one of the bellhousing bolts. Personally I run one.

 

[Starlight]

Thanks, we did have a good few rides "outback" before this happened. I will have the transfer case dropped and have a look. Bottom line is there should be no fluid between the transfer case and the "adapter" support ??? Thanks, Capt.T

 

[Bighorn]

I literally finished a t case rebuild and reinstall yesterday.
Although mine is a turbi 400 trans with the np 208 t case.
I had a leak where yours is and even orange silicone from a previous repair attempt hanging out.
That is what prompted me to tear the t case out in the first place.
Anyhow, there is an o ring seal between the transmission and adapter (rear trans mount) and a gasket between the adaptor and t case.
Yours seems to be leaking at the gasket.
That gasket was included in my t case rebuild kit.
I had fluid in the space between the trans and adapter because the rear of the trasmission is exposed.
The seal goes into the t case where the adaptor meets it and seals the input shaft of the t case.
There should be a support rod between the pass side t case and bellhousing.
Mine was missing so I bought one on ebay.
Good idea with these aluminum t cases and wheeling as it supports against the flex imposed by the output to the front axle.

 

[Chaski]

Thanks, we did have a good few rides "outback" before this happened. I will have the transfer case dropped and have a look. Bottom line is there should be no fluid between the transfer case and the "adapter" support ??? Thanks, Capt.T

There WILL be fluid in the adapter cavity, and it comes from the transmission. At least it is pretty easy to remove and install a transfer case on one of these with a buddy or a transmission jack.

 

[Starlight]

Great stuff ! Thanks guys. She sits in NOVA SCOTIA for 10 months . We love that rig. Only has 40k on her now and has never given us a problem or left us stranded in the woods and we go deep in . We gave her a good workout this summer and there were some areas I thought we'd be stuck but she brought us through every time.

Just to make sure I'm grasping all this... The spot were you see the leak should have a gasket ?? and there should be fluid there in that cavity ?? Thanks again, Capt.T

 

[Bighorn]

Great stuff ! Thanks guys. She sits in NOVA SCOTIA for 10 months . We love that rig. Only has 40k on her now and has never given us a problem or left us stranded in the woods and we go deep in . We gave her a good workout this summer and there were some areas I thought we'd be stuck but she brought us through every time.

Just to make sure I'm grasping all this... The spot were you see the leak should have a gasket ?? and there should be fluid there in that cavity ?? Thanks again, Capt.T

Where the cast iron adapter meets the aluminum transfer case; yes, a gasket is appropriate and comes in the transfer case rebuild kit even though the other parts of the np208 t case only call for silicone sealer.
Probably has to do with dis-similar metals meeting up.
I am sure you could buy just the gasket Itself someplace or just make your own out of bulk gasket paper.

Yes, if the truck is level you will only get a cup or two of fluid out of that cavity when you pull the transfer case.
That Is normal.
The tailshaft housing that would have been attached to your transmission if it were in a two wheel drive vehicle, has been removed and the transfer case is attached there so the input seal of the transfer case is what keeps fluid In your transmission now and keeps it separated from the transfer case fluid.

 

[Starlight]

That's great and thank you . It appears to only be form-a-gasket or some permatex for a gasket there. Many thanks for this input. I don't like regular auto mechanics working on this . There's only one guy up that way that I'll let touch it . He used to service the Canadian Military Motorpool up that way. Thanks again , T