Hi, guys I have evo 4 transmission oil leaking through the transfer case shaft, after a rebuild. I had all seals replaced with the new ones, so I am 100% sure I didnt miss anything.

I had no oil in trasfer case, as I just mounted it onto the transmission. And decided I would fill transmission full of oil, up to the top fill plug. At first everything was great.

After I came back from work. I was going to fill the trasfer case with the other oil which is thicker, I look on the floor and found out, the oil I filled in my transission leaked through the back of the shaft. I

didnt attach the shaft on trasfer case.

Are trasfer case and transmission 100% sealed from each other? I dont understand why the oil leaked through, could it be because i didnt fill trasfer case with its own oil? it did not leak right away. Thanks.

 

I don't know how far back the design goes but my Evo 8 transfer case differential compartment shares oil with the transmission and hence, the axles.

 

The drive shaft is not connected? Doesn't the drive shaft seal the t-case?

 

Yes it does. But I didnt fill the T case with Oil. Only the transmission. Thinking T case will block the transmission oil from coming out, since T case uses different oil. So i didnt bother mounting the shaft on.

 

Heres is basically what Im not clear about:
The black part number 1, uses different size oil than transmission right?
Is that oil gets shared with the Red part that I circled. Where it lubricates the worm gear for the T case and Diff with viscous large gear.
Transmission oil only enters the Diff with viscous on the inside and also lubricates the front shafts.
Am I correct?
So in other words, the Black Area and Red Area do not share fluids with the transmission, those are different chambers since there is a seal between transmission and the Red part. Except for the viscous coupler unit which has differential gears, taking transmission oil and gets lubricated from the inside. Right?

Has any one tried swapping their fluids, draining everything at once. Adding transmission fluid and see if it gets through the T case? I kinda have a feeling since I didnt have fluid on Transfer case side, the fluid in transmission pushed the seal a little open since there was no fluid pushing the seal from the other side. Which lead transmission fluid sipping in.

 

I try to write what I am 100% sure about. I've never had the transfer apart and most people are in the same boat. When the transfer fails it gets sent to a rebuilder.

However, there's a vent in my transfer case between the transfer and the transmission. So, oil sharing is going on. But there also is a vent to atmosphere. Looking at the FSM diagram it appears that transmission oil lubricates the front differential. I think the reason for this is that it is hard to seal with the shafting running through both. Gear oil lubricates the ring and pinion. If all this is true then transmission oil should not be exiting the tail housing.

I suggest you talk to one of the rebuilders to verify this.

 

Ok. I contacted jacks transmissions. Well see what they say.

I was looking through the forums...... and saw someone with similar problem of having a bad seal. I think I forgot to put that seal on completely, I dont even remember that inner seal to be installed. The one I marked in Red. I think im missing one. Going to have to check now....

 

Damn it..... nvm. I just pulled the cover off. I do have that seal on.... I added more oil in the transmission, looks like the oil coming through the other seal.....

 

Ended up finding out the seal was lose. I had evo 8 seal instead of evo 4 seal on. They are different apparently.

 

Thank you for posting the solution. So many people never report back, making the search feature pretty much useless.

 

So, the transfer case is from Evo4 and the car is Evo4?

 

When I was rebuilding my transmission, I ordered evo 8 seal thinking its the same diameter.... But it wasnt. So I had to look up Evo 4 seal part number and order those. Transmission parts were all the same between evo 4 and 8. The only thing is different is the Transfer case parts.

The car im building has G4JS Motor, mated to Evo 4 5 speed transmission. On 2006 Hyundai Tiburon. I went with that motor because its a long block with oil squrters already in. And the heads are cheap. G4JS are all over the junk yards. Rebuilds are cheap. Takes away high cost of finding actual Evo block or head, if they brake. I used nothing but Evo parts in my engine rebuild, except for the oil pump and an oil pan. G4JS can be picked up 100 bucks for the head and 180 for the block!!!!!!

https://www.newtiburon.com/forums/ti...g64-build.html

Check out my thread on the other forum. Maybe it will help someone who wants to use one of these motors in their evos.

Also, if any one want to follow my instantgram it has most of my recent pics on the build. Romulus_6

And please dont hate, Ive been an EVO fan for quite a while. I wanted something unique and I always loved my car as well. So I came up with this crazy idea of an engine swap. I always wanted an EVO, but never happen to buy one....