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Where is this transmission fluid leaking from?

Where is this transmission fluid leaking from?

Postby ChevyThunder [OP] » Sep 17 2012, 12:58am

Image

This picture is taken looking toward the front left of the truck. I believe that case at the top is the center differential.. but what could cause this fluid leak. I'm about to try a transmission rebuild on this thing and would like to solve this leak while I'm at it.
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Re: Where is this transmission fluid leaking from?

Postby ASTE25 » Sep 17 2012, 2:07am

It looks like the gasket between the transmission extension and the transfer cased is bad.
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Re: Where is this transmission fluid leaking from?

Postby Machster69 » Sep 17 2012, 2:09am

I think it is the seal btw the trans and transfer case...
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Re: Where is this transmission fluid leaking from?

Postby ASTE25 » Sep 17 2012, 2:13am

There appears to be an echo in here.
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Re: Where is this transmission fluid leaking from?

Postby Machster69 » Sep 17 2012, 2:21am

I jus changed the wording :D
guess I coulda did the typical
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Re: Where is this transmission fluid leaking from?

Postby ChevyThunder [OP] » Sep 17 2012, 11:59pm

Yeah, once you said it was the transfer case I was able to find a input shaft seal and output shaft seal for the case at RockAuto. I guess that is their terminology for the one that goes to the front driveshaft and the rear driveshaft. Both seem to be leaking a lot of fluid.

Next problem I ran into is I'm trying to get the front driveshaft removed but cant access the retainer bolts on the transfer case side. So I'm trying to remove the crossmember. I've taken off the two nuts and bolts on both sides of the frame and the two nuts in the middle that attach to the transfer case bushing, but its barely budging.
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Re: Where is this transmission fluid leaking from?

Postby ASTE25 » Sep 18 2012, 1:18am

There is also a paper gasket that fits between the transmission extension and the transfer case (which is what looks like is the part leaking on yours). There is an input seal to the transfer case on the input shaft of the transfer case you will see once you get the transfer case out. That would not cause leakage to the outside of the unit if it was leaking. If it was bad it would allow fluid to leak from the transfer case into the transmission and vise versa. The output seals for the transfer case would be the seals to each driveshaft.

You may know this, but I'll tell you just in case you don't: You have to support the transmission when you remove the crossmember. You should be able to get the front driveshaft off without taking the crossmember out.
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Re: Where is this transmission fluid leaking from?

Postby ChevyThunder [OP] » Sep 18 2012, 10:57pm

I'm getting a little more than I bargained for with this one. The previous owner did some mudding so I'm getting sand in my eye with every turn of the ratchet, etc.
Once I lifted the transmission the crossmember came out pretty easy. I may have lifted it too far because that transfer case/ transmission gasket started leaking more once it was up. If I do this again, I'll use the pry bar as much as possible against the bushing to keep from straining the bolts between the transfer case/ transmission.

On that front driveshaft, I got the front side free but the transfer case side is still stuck.
Image
Any ideas?
Also the front axles don't have to come out for the transmission to drop do they? Sorry about all the questions, my service manual is in the mail.
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Re: Where is this transmission fluid leaking from?

Postby ASTE25 » Sep 18 2012, 11:26pm

Take the (4) 11mm head bolts (i think that is the size they are) holding the front u-joint to the yoke and it should come right out (you may have to pry a bit with a screwdriver). Be sure not to allow a u-joint cap to fall off and knock the needle bearings out of place. The front axle does not have to be removed to take the transfer case out.
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Re: Where is this transmission fluid leaking from?

Postby ChevyThunder [OP] » Sep 20 2012, 6:50pm

I pulled the pan yesterday and found this:
Image
About 8 paper towels worth of sludge there.

My manual came yesterday and evidently there were three transfer cases used in 1994:
NP 241
Borg Warner 4401
Borg Warner 4470
The NP case has a square fitting for the front drive shaft while the BWs have a round one. You can tell the 4401 from the 4470 because the 4401 has splines going lengthwise along the case. The 4401 is pictured.
Image
I'm still not sure what the adapter to the left of the case above is called. I did find why it was leaking though. There was just a silicone bead instead of a gasket on the transfer case side of the adapter and the transmission side was missing two of the 4 15 mm (?) bolts. People like me without pneumatic tools will need ratcheting wrenches for those 4 bolts and the 6 15mm oneson the transfer case side as well.
Image
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