5R55E, pressure in extension housing to BW4405?

[wollimann]

Hello,

this is the second time that i miss 1,5 liter of automatic transmission fluid. The firts time i found that missing oil
inside the transfer case. Changing the seal input ring (other two rings too) of the Borg Warner 4405 and that should
fix the problem.
For a while the problem was fixed, now (in a couple of days) the same amount of trans oil is missing.
I have to look if the transfer case oil level ist too high, but it is too cold outside to crawl under the car.
There are no other leaks of trans fluid, so i suppose it is the same issue with the seal ring.

But why does it happen? Is there a high pressure inside the extension housing which could move the oil into the transfer case?
Or is it normal that the seal fail its service?
It is a Motorcraft seal, not the one with the metal flange.
I am very annoyed of taking out the transfer case too often,
but i love my 96 Explorer 4.0 sohc and will fix it as soon as possible.

Are there any thoughts of that issue?

kind regards

Wolfgang

 

[C420sailor]

To clarify...you are losing 1.5qts of fluid from the transmission and finding it in the transfer case?

 

[XLTrunner]

I didn't know that was even possible. Have never heard of tranny fluid infiltrating the transfer case.

 

[imp]

Hello,

this is the second time that i miss 1,5 liter of automatic transmission fluid. The firts time i found that missing oil
inside the transfer case. Changing the seal input ring (other two rings too) of the Borg Warner 4405 and that should
fix the problem.
For a while the problem was fixed, now (in a couple of days) the same amount of trans oil is missing.
I have to look if the transfer case oil level ist too high, but it is too cold outside to crawl under the car.
There are no other leaks of trans fluid, so i suppose it is the same issue with the seal ring.

But why does it happen? Is there a high pressure inside the extension housing which could move the oil into the transfer case?
Or is it normal that the seal fail its service?
It is a Motorcraft seal, not the one with the metal flange.
I am very annoyed of taking out the transfer case too often,
but i love my 96 Explorer 4.0 sohc and will fix it as soon as possible.

Are there any thoughts of that issue?

kind regards

Wolfgang

The 4X4 design uses an ADAPTER situated between the transmission and transfer case, instead of an "extension housing". The adapter bolts to the transmission and the transfer case bolts to the rear part of the adapter. The transmission has it's own output shaft oil seal, and a short splined shaft protrudes through to engage the transfer case input shaft. The transfer case input is sealed by a special double-lipped oil seal which is designed to EXCLUDE transmission fluid from entering the transfer case. The second seal lip, facing inward, prevents transfer case oil from leaking into the adapter.

Both seals must be in good condition to work effectively. Any leakage from either transmission or transfer case into the adapter is intended to be bled out and away through a tiny hole provided in the bottom of the adapter.

There should be NO PRESSURE within the transmission, or transfer case. Both have VENT provisions to the atmosphere. A clogged transmission vent would surely force oil out past seals.

This is how my '96 worked. Other schemes may have been used with other transmission / transfer case combinations.

 

[wollimann]

The 4X4 design uses an ADAPTER situated between the transmission and transfer case, instead of an "extension housing". The adapter bolts to the transmission and the transfer case bolts to the rear part of the adapter. The transmission has it's own output shaft oil seal, and a short splined shaft protrudes through to engage the transfer case input shaft. The transfer case input is sealed by a special double-lipped oil seal which is designed to EXCLUDE transmission fluid from entering the transfer case. The second seal lip, facing inward, prevents transfer case oil from leaking into the adapter.

Both seals must be in good condition to work effectively. Any leakage from either transmission or transfer case into the adapter is intended to be bled out and away through a tiny hole provided in the bottom of the adapter.

There should be NO PRESSURE within the transmission, or transfer case. Both have VENT provisions to the atmosphere. A clogged transmission vent would surely force oil out past seals.

This is how my '96 worked. Other schemes may have been used with other transmission / transfer case combinations.

Hi IMP,

this is my revised 5R55E and at the end of this tranny i thougt it was a extension housing, thank you for the "adapter" information.
Pulling out the tranny or the transfer case, there were always tranny oil inside the adapter (but not much).
In my opinion there is no seal (could not found one) at the end of the tranny.

A special double lipped seal at the input of the TC, i never heard of this or looked at it for lips with both directions.
Maybe i ordered the wrong seal number at the first pullout of the TC?
That would explain how the tranny oil gets into the TC.
But there must be a xyz pressure inside the adapter to push this ammount of oil into the TC?
The first time the TC was so full of oil, it squirts out of the vent tube.
So the temperature inside the TC rises and the sound changes, like an big e-motor.

Now i am pretty shure that i had ordered the wrong seal ring (but they have all the same order number...).
Upper ones are Motorcraft, lower ones included in a bw4405 repair kit from Rockauto..

thanks for your information!

Wolfgang

 

[imp]

Hi IMP,

this is my revised 5R55E and at the end of this tranny i thougt it was a extension housing, thank you for the "adapter" information.
Pulling out the tranny or the transfer case, there were always tranny oil inside the adapter (but not much).
In my opinion there is no seal (could not found one) at the end of the tranny.

View attachment 327646

A special double lipped seal at the input of the TC, i never heard of this or looked at it for lips with both directions.
Maybe i ordered the wrong seal number at the first pullout of the TC?
That would explain how the tranny oil gets into the TC.
But there must be a xyz pressure inside the adapter to push this ammount of oil into the TC?
The first time the TC was so full of oil, it squirts out of the vent tube.
So the temperature inside the TC rises and the sound changes, like an big e-motor.

Now i am pretty shure that i had ordered the wrong seal ring (but they have all the same order number...).
Upper ones are Motorcraft, lower ones included in a bw4405 repair kit from Rockauto..
View attachment 327647

thanks for your information!

Wolfgang

The dual-lip seal for the transfer case input shaft has 2 garter springs, and looks like this in cross-section:

The lip of an oil seal excludes oil flow in the direction of the shorter edge of the lip. Thus the double lips exclude oil flow from EITHER direction.

 

[drdoom]

As mentioned above, check the atmo vent(s). I had one plugged by insect stashing their food. Caused a bad fire when the torque converter went out.
Also, the seals bottom row in the photo, those are totally jingus. Use ones like the top row.

 

[donalds]

. Use ones like the top row.

I have used them style felpro seals
Work great very easy install

 

[wollimann]

I have used them style felpro seals
Work great very easy install

Thanks for the information!
Today two seal kits from CobraTransmission arrived, so i
can put them into my two spare transfer cases.

This was the last action in summer...

...now again transfer case, Explorer is a challenge
with high mil.

Wolfgang

 

[imp]

Thanks for the information!
Today two seal kits from CobraTransmission arrived, so i
can put them into my two spare transfer cases.
View attachment 327679

This was the last action in summer...
View attachment 327680

...now again transfer case, Explorer is a challenge
with high mil.

Wolfgang

Be certain to place a few gobs of good quality grease in between the 2 lips of the seal before installing it. Rubber sealing elements need lubrication too, to prevent overheating and premature wear-out. The 2-lip design tends to exclude all oil from between the lips.