Transfer case leak where the two halves come together

6716

Original poster
Member
Jul 24, 2012
822
So today after the vehicle sat in the garage for like two hours, I noticed a little puddle where there wasn't before. The transfer case is dripping, looks like it's coming from where the two halves come together.

Now, I just towed a full 6x12 U-haul trailer 330 miles on the interstate yesterday, and then towed it back empty today.

Don't know if the problem is related or due to the towing, or the mileage (200K) on the truck, or both, or neither or something else.

I guess I'm hoping it's like a gasket or something.

Didn't seem to have any performance issues while towing, or after towing.

What's the best way to figure this leak out?
 

6716

Original poster
Member
Jul 24, 2012
822
I think it might be the transfer case output shaft seal -- front.

The transfer case is wet on the front, and not any on the back, so it's not the fill or drain plugs. And it's wet a bunch all over the front, so it's not like there's a main gasket leak where the two halves come together.

And it is wet where the shaft comes out of the transfer case.

Questions:

Am I dead in the water until I get this fixed?

Does the troubleshooting sound likely? Anything else it might be? if it is this, is it a sign of some other problem, or the seal just decided to quit at 200K miles?

Anyone out there replaced this shaft seal?

Does it really require the "special tools" the manuals suggest?

May as well replace the LCA brackets if I want new bushings anyway while I'm at it since it looks like those come off in the procedure?
 

6716

Original poster
Member
Jul 24, 2012
822
Here's a video I found for the rear output seal on an older GM truck.

This helps the visualization.

[video=youtube;esFT1doSSyo]http://www.youtube.com/watch?v=esFT1doSSyo[/video]

How To Install Replace Transmission Transfer case Tailshaft Seal 1AAuto.com
 

navigator

Member
Dec 3, 2011
504
how much fluid have you lost?
I would keep a check on the fluid, if it is losing fluid slowly then you have more time to fix it.
If it is losing fluid quickly then you have less time.

Make sure to use the AutoTrakII fluid.
 

6716

Original poster
Member
Jul 24, 2012
822
navigator said:
how much fluid have you lost?
I would keep a check on the fluid, if it is losing fluid slowly then you have more time to fix it.
If it is losing fluid quickly then you have less time.

Make sure to use the AutoTrakII fluid.

Tough to say in total how much I've lost without getting into the fill plug I suppose, and I don't have that tool, or even know what it is.

I just started pulling it all apart. I've got a couple more trailer loads to run a total of 1500 miles, and I would be a lot less anxious if I got it fixed.

I've got the drive shaft out of the U joint, but I can't pull the shaft out of the transfer case. I don't know if there is a trick to it, or just use more force. I can see the spindle in there, the dust cover is moved back, but it just hasn't come completely free just yet.

Any ideas on that?
 

6716

Original poster
Member
Jul 24, 2012
822
fuuuuuuuuuuuuudge

The fluid on the floor looked pinkish like transmission fluid. Now that I have the seal off, the fluid that came out of the transfer case (and I'm going to have to refill it now) is like blue-green. Not pinkish.

So, that's my concern, that I am replacing this seal, since I have it off, but it may not be the problem.

Is the fluid color any indication?

shoot
 

6716

Original poster
Member
Jul 24, 2012
822
So, if it wasn't the seal, because the fluid colors don't match up .... grrr, I wish I had thought about double checking the color before I got it all apart .... what are the other options for leaking red fluid in that area?

A gasket where transmission meets transfer case?

The leak rolls from wherever and drips down from the bottom of the transfer case.
 

jpimp

Member
Feb 1, 2013
176
lol yes. breaking stuff does count as a mod.

but anyways...
if i'm reading this correct... it sounds like you have a transmission fluid leak at the back of the transmission where it meets up with the transfer case.
There is a seal that keeps the transmission fluid in the trans that is probably shot for you.
I haven't opened up my GMT360 yet but I think it could be either a paper gasket or a constant motion seal. either way transfer case has to come out to repair

Hope this helps.

-J
 

6716

Original poster
Member
Jul 24, 2012
822
jpimp said:
There is a seal that keeps the transmission fluid in the trans that is probably shot for you.
-J

Unfortunately, I do believe I am coming to the same conclusion.

I can't find the information for this repair in the manuals.

Well, it'll be easier to get the front output seal back in I think.

Am I going to lose ATF when I do this repair?
 

6716

Original poster
Member
Jul 24, 2012
822
Are we talking about the transfer case gasket here?

Is that supposed to be holding in red fluid or blue fluid?
 

Hatchet

Member
Nov 21, 2011
2,405
Transfer case is blueish fluid.
Tranny is red
Coolant is orange
 

jpimp

Member
Feb 1, 2013
176
I have not had my gmt360 apart yet but I'll try and explain...

On other vehicles i've had apart there is usually a constant motion seal on the transfercase that holds the transfer case fluid in and keeps the transmission fluid out of the transfer-case.
there is also a paper gasket in between the transfer-case and transmission case that keeps the transmission fluid from leaking onto the ground.
This paper gasket is what I think you might need to pelace if you fluid on the ground is red.
But be sure to check where the extenstion housing bolts to the transmission case that it is not leaking at those case half of the transmission.

Hope this helps.

-J
 

6716

Original poster
Member
Jul 24, 2012
822
To come full circle on this one, other than doing transfer case work that wasn't the problem .... I never did any more work on this issue and I'm still driving along just fine.

I've towed twice more, once with a U-haul 6x12, once with a 5x8 and I didn't have any problems and I didn't see any more transmission fluid on the ground.

But I park differently now that we're moved to the big city and all -- no more big 'ol garage for me -- so I'm not sure how well I'm noticing fluid on the ground where I park.

Still, I don't have any shifting problems.

The U-haul guy thought that maybe the transmission fluid got hot enough that it thinned out and made it through the gasket.

I officially don't know.
 

misterhyde

Member
Oct 14, 2012
34
So I just towed a small boat, no cover, about 300 miles, doing 75mph in D most of the way (maybe 45min. at 70). Ended up I was spraying some sort of fluid for most of the way and did not know it until I stopped 100 miles from home.
Got under the truck today and the lead is coming from the gasket between the two halves of the Transfer case. But it is reddish fluid and not blueish. And I just had the Transfer Case fluid changed 8 months ago by local shop. Receipt says AutoTrak II, 2 quarts.
I think I have a call to make tomorrow. Maybe even leave it there in the morning for them.
(2005 TB LT, Swb, 4x4, 120k)
 

Hatchet

Member
Nov 21, 2011
2,405
Red is tranny fluid. Might be coming from the output shaft of the trans.
 

misterhyde

Member
Oct 14, 2012
34
Hatchet said:
Red is tranny fluid. Might be coming from the output shaft of the trans.

That's what I thought before going under to see. I wiped everything down with paper towel and waited 10 or 15 minutes. Went back under and it was definitely coming from the gasket between the halves.
Is it true that no transmission fluid makes it to the transfer case, since they are mechanically separated?
I just want my ducks in a row when I go back to the shop and ask them to check the color of the transfer case fluid they put in.
 

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