I have looked up so much information on this, and I'm still at a loss, so here I am.
I'm definitely not a mechanic, I can change fluids and have understandings of functions/purpose of mechanics.
So the banjo fitting, coming from the ACD pump -> to the top of the transfer case had a very small leak. I snugged the bolt up, and it was dry for days. (picture below)

The reservoir has been going empty (went dry the first day it started to empty, I had missed it) I refilled it, and the 3 lights went out.
The attached picture shows where the reservoir is after 15-20m of driving, and letting it cool over night.
For a while - no fluid came out of the transfer case (I think it was leaking, then blowing back a bit, burning on the exhaust)
I had to drive on the freeway for about a mile or two (70mph), and knew it was going to be leaking, so I went straight home, and the vent on the top of the transfer case had a lot of oil around it, which is new to me (picture below).

I am at a complete loss for what is taking place.
Where is the ACD fluid going, can it bleed into the transfer case itself?
The plate that is on top of the transfer case, that holds the vent valve, is there a gasket between it (the plate) and the tcase that could also leak?

I thought of changing the transfer case fluid, and see if it looks like a mix of fluid. I had bought the car two months ago, and I'm not 100% sure what fluid is in the transfer case from the previous owner.
Any information would be greatly appreciated.

 

looks like it is not hte banjo but the overflow from the breather on top of the transfer. This is not good as it means your acd piston in the transfer box is leaking... it is basically two large O rings inside, but you do need a specialist to fix...

 

The more I read into the system, and what is happening to the car, I think you are correct.
ATF is bleeding from the ACD into the transfer case, and then being spit out the breather.
I'm going to call the shop Monday, and have them tear it apart, it is beyond my knowledge. I wish I had the confidence to do it

I'm guessing since they will have the transfer case out of the car, I might as well replace any gaskets they come across. Do these gaskets normally have leaks after so long? The car is a 2005, so 14 years old, but only has 38,800 miles on it.

 

No gaskets but lots of o rings. The mileage is a bit low for such a problem but who knows.

 

im sure it is filling up the transfer case with ATF fluid.
hopefully it hasent damaged the transfer case running in that really thin fluid.

pull and rebuild.

i love my non acd transfer case

 

The transfer case itself makes no odd noises, after looking up what a failing transfer case sounds like.
But it seems like a good point to stop and get it fixed before it does destroy itself.
I'll send it out and have them inspect it, rebuild it if necessary, but mainly replace all of the o rings so I don't have this problem again for a while (hopefully never).

Thanks for the help, I lurked around on the site for a while before finally posting - glad I did!

 

get shep or jacks to build it.

both are good. shep turned my last one in like 2 weeks.... which was quick.

 

Two weeks isn’t bad at all.
Even if the shop I’m dropping the car off at can get it to stop leaking fluid and inspect the gears, I will be content.
I’ll just prepare next year or this winter to tear it out myself and get it rebuilt. I’m just starting to understand the car, a bit hesitant to work on it just yet to be honest.

I’m assuming a rebuilt transfer case should last a long while, they put in stronger gears, and not just brand new ones?

 

Usually OEM which is pretty stout as is. TRE can shot peen/detail the gear which will make them stronger also.

 

Mine leaks too. Have to take it out to diagnose it.

 

That's good news. I've always heard the drive train on evo's are fairly decent, mostly 5 speed transmissions (except 5th gear at high rpm)
Monday is my appointment, I will post their findings and fixes as I get them. I figure any information can be useful


I just came home to the car leaking a good amount of fluid out. I'm guessing it's what has bled into the transfer case from the ACD side. It's pink fluid, but smells like gear oil.
I'll pay for a tow to the shop and let them look at it. I'm guessing the seals are bad inside, the car makes no odd noises. I drove it about 2 miles down the road to my brothers house Saturday, and then just parked it.
So the fluid is still making it's way into the t case, and out the breather.

As odd as it sounds, I should be upset - I've only owned the car for two months. However I prepared for repairs, seeing as these cars are getting pretty high in age. Mine has low miles, but 14 years is 14 years, and I have no idea how the previous two owners treated the car.

Thanks again for the replies, I hope I can help someone down the road, and repay the favor.

 

Just unplug the ACD pump and change the oil in the transfer case... then you can drive normally untill you are ready to fix the car.. (just bear in mind that the central diff lock will not work)

 

I let the car sit for about 4 days and it emptied the reservoir for the ACD. I slid a pan under the car to catch the oil and have been cleaning it off daily since it is corrosive. Still coming out of the transfer case breather.
If I were to drain the ATF that is in the transfer case, and put fresh gear oil in, then unplug the ACD pump, wouldn’t it still leak in? Or should I just drain the reservoir and get rid of as much ATF as possible?

This would be so much easier than dealing with it puking out fluid everyday. I didn’t refill the ACD reservoir since it leaks out anyways. But it’s also been sitting, and I haven’t been driving it.

 

no, it is leaking because it is overfilled with hydraulic fluid... Just unplug the electrical connector for the pump, drain the fluid from the transfer box and replace with proper gear oil... (using the fill point on the transfer box, not the acd pump..)

 

and no, the acd pump fluid is not corrosive..