I'm installing a SYE and see that my transfer case is bleeding honey rather than blood.

Any thoughts on how to deal with this?

Can I just drain what I can, and replace it with ATF?

Run it a few hundred miles and then replace it again?

Or are the two lubricants so incompatible that I need to aggressively clean out the gear oil.

 

Fill drive 10 miles flush.

Repeat 2 times and should be good to go.

 

This would certainly be fine. Personally, I'd probably just drain it and fill with ATF and go.

 

If it is filled with engine oil, Rockland Standard Gear, Inc. recommends using 10w30 synthetic engine oil in all Jeep NV transfer cases instead of ATF, primarily due to excessive misting/venting problems that tend to cause the fluid to dissipate quickly without the owner's knowledge. Chances are, the previous owner did just that, as I did when I owned my 2005 Unlimited. Both TC and transmission in mine were filled with 10w30, and both worked much better because of it. I would imagine the new owner was just as surprised when he performed fluid changes.

If it's filled with gear oil, someone was terribly misinformed. I don't believe I've ever seen anyone put gear oil into a transfer case before.

 

Are you sure it's gear lube? Does it smell like it?

Not sure about ATF and gear lube mixing okay but the seals in the TC will not get along with gear lube.

If it is gear lube, get some and put it in a container then add some ATF to the container, stir, and see how they mix. If they look like they will blend okay drain and refill the TC with ATF, drive it around the block and repeat (several times).

If they will not bled okay...punt.

 

Ooops..dupe post. Ignore...

 

I have a cold on top of having no sense of smell to start with. I won't be able to ID is by scent. It is definitely not ATF.

The transfer case doesn't look like there are too many seals to swell.

What ever it is does seem to mix with ATF.

I'm not sure how much circulation of oil occurs in the transfer case, especially if you aren't in 4wd. Is a mile or two enough?

 

Even without a sense of smell you should notice your lungs burning lol. Hmm maybe thats only with brake cleaner too

Remember the transfer case is in operation all the time. There's an oil slinger/pump near the output shaft that moves fluid around. I'd give it a little linger than a mile just to slosh around and work on the walls.

Never heard about running non-ATF in the 231. Interesting.

 

No real distinctive smell to the oil but is is definitely a higher viscosity than 10w30 and kind of "sticky"

After splitting the transfer case, everything inside is pristine. No real signs of wear at all which I find surprising given that the car has 228K miles on it. I have no idea if it has been replaced at some point though.

I have enough of it apart that there aren't a lot of places for oil to hide so whatever it was is pretty much gone.

 

If the TC still has a data plate on it you can determine date of its manufacture. In the serial number spot on the data plate you should see the date of manufacture, MM DD YY. If it's the original TC the date should be pretty close to the date of manufacture of the vehicle.

What does that "sticky" stuff taste like?

 

i just picked up my xj and was going to change out all the fluids until i realized the tc calls for atf. i know chevy runs atf in their tc's but all the other vehicle i have ever worked on used gl4 or gl5 in their tc's. just curious as to why you wouldnt run gear lube as atf has practically zero lubrication properties for seals etc.

 

Sure it does... you don't think automatic transmissions have seals? lol

NPG/NVG has specced ATF of various types in their small transfer cases for decades. You can run motor oil in some if you want.

The 231 in specific has a brass synchronizer ring to engage the front yoke. I wouldn't put any GL5 fluid anywhere near that thing. Also you'll want to stay within a certain viscosity range to keep the oil pump working (which other gear boxes don't have)

 

fair enough, any idea about how much fluid will cost for the tc. its not a big deal just so i know

 

Really cheap, there's only about 1.8L in there. Two bottles of your favorite brand of ATF+4 or D/M and good to go!

 

From what I understand you'll want to run ATF+4 for your transfer case.
$6.99/Qt, I bought 3 Qt's you shouldn't need that much



Be sure to get somthing to help you fill your transfer case, you won't be able to just pour it in the fill plug....