OK Gang, Tell me about the Transfer Case

[Timdeb4397]

I just purchased (Thurs) a 1997 Eddie Bauer V8 with 120,000 miles on it. Upon taking a trip today from Cincy to Columbus. (100mi or so) I noticed what appeared to be a fluid on the rear window. As it turns out, this fuid was coming from under the truck!! Upon further investigation, it appears to be coming from the transfer case.

Here is where it gets a little tricky... I have a Haynes manual that shows where the drain plug is on "a" transfer case. In the picture the drain plug is behind the damper. On my truck, first, there is no damper and if there was a drain plug would not be there. I can see the four mounting holes for the damper and 2 plugs to the right of the of where the damper would be. These plugs, ( both look like the drain plug in the Haynes manual) are about 3 to 4 inches apart, a little offset but one over top of the other.

I figured that the upper one was the fill plug and the lower was the drain plug. So, I removed the upper plug only to have fluid ( which appeared to be same color and viscosity as what appeared to be leaking) come rushing out!!! Now, if this is the fill plug, the transfer case was overfilled. If the upper plug was NOT the fill plug then I just drained A LOT of fluid out of the case.

According to the Haynes manual an overfilled transfer case can cause a fluid leak. As it was getting dark and I am not at home, I could not find the vent tube which should have been the source of the leak, IF the case was overfilled.

Here are my questions to you ... the experts;

1. Was the upper plug the fill plug?

2. Where can I find a diagram showing the transfer case that a 1997 AWD vehicle would have?

3. The fluid was very dark. If replaced would it do more harm than good?

4. If the upper plug was not the fill plug where is the fill plug? I ask this because I do not see how the transfer case could get so overfilled unless I had the wrong plug?

That should do it for now, any insights or observations would be greatly and humbly appreciated.

 

[IZwack]

1. Was the upper plug the fill plug?

2. Where can I find a diagram showing the transfer case that a 1997 AWD vehicle would have?

3. The fluid was very dark. If replaced would it do more harm than good?

4. If the upper plug was not the fill plug where is the fill plug? I ask this because I do not see how the transfer case could get so overfilled unless I had the wrong plug?

That should do it for now, any insights or observations would be greatly and humbly appreciated.

the trasnfer case probably wasnt overfilled. most fluids expan when they get warmer in temperature.

one easy way to overfill a transfer is to fill it up when the vehicle is parked on a hill pointing down.

and yes the top plug is always the fill plug - so u had it right.

no u wouldnt do any harm to the tranfer case by filling it up with new fluid - just make sure you get the proper fluid - which i bielieve is Dexron-III\Mercon Automatic Transmission Fluid (ATF)

 

[Timdeb4397]

Thanks IZ

The thing is... is that the truck had been sitting for at least 2 hours before I removed the plug and when I did, it came out just as if you had just started draining your oil!

But, if the level was OK.... Then I guess I should let it sit overnight before checking.

I was really hoping it was just overfilled.

 

[IAmTodd]

How can you tell it was coming fron the TC if you didn't see where it was leaking?

 

[Timdeb4397]

That is an Excellent question Todd!!

There was fluid sprayed all underneath the truck from the Transfer case to the rear. The transfer case area appeared to be the source based on how things looked.

Now, while the TC had a bead of fluid ready to drip from it, (it was not visably dripping) The undercarriage on the driver's side of the TC was "wetter" than the passenger side.

Another piece to the puzzle is that once dried the fluid was a bluish-green tint. This was the same color as what came out of the TC when I pulled the fill plug.

 

[IZwack]

wow bluish-green .. thats amazing. there are some od collored fluids out there but most of the time, Mecron/Dexron is cherry red (when new) and turns dark redish-brown when really old.

one thing that sometimes leaks is the O-rings around the speed sensor... just a thought.

 

[V8BoatBuilder]

I have the same transfer case as you, its a BW4404 AWD t-case. Single speed, viscous coupling front shaft.

As has been said, the upper plug is filler, lower is drain. Fill the case with Mercon/Dexron III red transmission fluid untill it runs out the upper port.