Xfer case leaks or normal behavior?

[Squishymonster]

I put a 2nd round of ATF into my xfer case to flush out sludge. Filled it slightly past the fill hole and a few seconds later it was dripping out the front and back at a pretty good pace.

There was plenty of ATF when I drained it so I'm sure it's related to over filling.

[https://youtu.be/KRjIV-OybJg]

[Rus Curtis]

That's ATF dripping out?  If I over fill, I usually just let it run out the filler hole until it stops (then it's at the correct level).  It's possible the seals have been compromised with what you had in there before (the mud/rust/goop was holding it all in).  It could also be possible the ATF is leaking through the splines or around the seal. The front shows behind the yolk so probably not the splines there. I suspect the seals may be worn.  ATF is thinner than gear oil.  It's possible that if you finally get back to putting gear oil in it may leak (but I bet at a slower rate). 

If that is your second flush, add some more and go drive it (a little overfill in this case wouldn't hurt anything).  The transfer case has a breather on top so if need be it will slosh out there also.  Maybe park it over some kitty litter or a bucket until you get it sorted out.

[athawk11]

I agree.  The seal surface can get chewed up pretty badly if the 3A wasn't maintained.  Replacing the seal only won't stop the leaks if the seal surface looks like the one pictured below.   You can stop the leaks by installing a Speedy Sleeve, new seals and some Permatex 2 sealant on the splines.  It's an easy project, but do this in conjunction with one of the times you plan on draining the gearboxes.

[Bruce_W]

  You’re running an abrasive slurry through your transmission and transfer case. Perhaps the abrasive wore the seals away. Also, the atf may have softened those old, hard seals and allowed them to leak. BW

[Rus Curtis]

Replacing the seal only won't stop the leaks if the seal surface looks like the one pictured below. 

I'm glad you brought this up!  How true.  I had to turn/polish one of my yolks.  Fortunately, it wasn't so bad I need to install a Speedy Sleeve.

[Squishymonster]

  You’re running an abrasive slurry through your transmission and transfer case. Perhaps the abrasive wore the seals away. Also, the atf may have softened those old, hard seals and allowed them to leak. BW

Yes, true. If I've caused any additional damage, that's clearly on me. I have only put on maybe 8 miles in this state, just for testing and fluid cycling - the jeep is not in joy riding phase yet. It would be far better to do a full tear down and rebuild so that I can bench clean the parts without friction & heat, so I am taking a gamble with my approach.

I suspect that over the summer I'll be picking up my CJ2a drivetrain and rebuilding that for a swap, but mixing parts sort of bothers me. Maybe I'll just try to do a rapid drop, rebuild, reinstall over a couple of weeks later in the summer.

The other gaskets I've come across have been in really rough shape. Thermostat, front and rear diffs, and shift tower were all pretty crusty and just about fused with the metal. The wheel cylinder rubbers were practically plastic. The oil pan gasket is also pretty rough but I haven't removed it yet. Fun story, I purchased an oil pan gasket and had it in a box where a mouse made a nest. It used part of the gasket. I hope it helped keep it warm...