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Unread 07-17-2013, 05:29 PM   #1
Why J?
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NP231 Input Seal Leaking......Again!

I recently rebuilt and my NP231 adding a wide chain kit hoping it will survive behind my LS. Anyhow before the rebuild the input seal leaked because I had installed it wrong side out. So when I rebuilt it I put in a new input seal and input seal retainer.

I noticed today that it is leaking again. I haven't dropped the tcase yet but I was curious if there is anything I should be aware of that could also leak? Is there a seal that is better than the OEM, maybe a double lipped seal?

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Unread 07-17-2013, 05:40 PM   #2
bigbossd1030
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Quote:
Originally Posted by Why J?
I recently rebuilt and my NP231 adding a wide chain kit hoping it will survive behind my LS. Anyhow before the rebuild the input seal leaked because I had installed it wrong side out. So when I rebuilt it I put in a new input seal and input seal retainer.

I noticed today that it is leaking again. I haven't dropped the tcase yet but I was curious if there is anything I should be aware of that could also leak? Is there a seal that is better than the OEM, maybe a double lipped seal?
The condition of the shaft should be taken into consideration. Any scoring or scratches can cause a leak. Emery cloth can normally cure this. Depending on how deep the scoring is if any. If its too deep, sanding it down will reduce the diameter of the shaft and the seal won't seal anymore.
When you say it leaking again, is it just a small puddle or a few drops on the ground? Or can you see exactly where it is coming from?
Not sure about the seal brands, I use generic from napa. Seems to work for me.

Sent from my iPhone, probably because I am bored at work.
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Unread 07-17-2013, 05:43 PM   #3
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Quote:
Originally Posted by bigbossd1030 View Post
The condition of the shaft should be taken into consideration. Any scoring or scratches can cause a leak. Emery cloth can normally cure this. Depending on how deep the scoring is if any. If its too deep, sanding it down will reduce the diameter of the shaft and the seal won't seal anymore.
When you say it leaking again, is it just a small puddle or a few drops on the ground? Or can you see exactly where it is coming from?
Not sure about the seal brands, I use generic from napa. Seems to work for me.

Sent from my iPhone, probably because I am bored at work.
Ill check the i put shaft and post so e pics when I get it out.

It is just a small leak right now. It is only enought to make a wet spot on the bottom of my skid plate. No drops on the ground under the rig yet.
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Unread 07-17-2013, 05:51 PM   #4
bigbossd1030
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Quote:
Originally Posted by Why J?

Ill check the i put shaft and post so e pics when I get it out.

It is just a small leak right now. It is only enought to make a wet spot on the bottom of my skid plate. No drops on the ground under the rig yet.
Okay, and it's at the front of the skid plate, under where the input shaft is then. And you are sure it's ATF?

Sent from my iPhone, probably because I am bored at work.
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Unread 07-17-2013, 05:56 PM   #5
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Quote:
Originally Posted by bigbossd1030 View Post
Okay, and it's at the front of the skid plate, under where the input shaft is then. And you are sure it's ATF?

Sent from my iPhone, probably because I am bored at work.
It is between the transfer case and the trans. It appears to be ATF.

The trans is a brand new Mopar NV3550, less than 1000 miles on it. So I do not suspect the out seal on the trans.
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Unread 07-17-2013, 06:07 PM   #6
bigbossd1030
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My guess is the shaft is scored up or the seal isn't seated right. Did you apply rtv around the seal before you installed it? I always do that and I have never had a leak. Also make sure the area where the seal sits isn't scored as well

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Unread 07-17-2013, 06:10 PM   #7
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Which way should the seal be installed?
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Unread 07-17-2013, 06:10 PM   #8
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New retaier and no RTV around seal.
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Unread 07-17-2013, 06:13 PM   #9
bigbossd1030
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Quote:
Originally Posted by Why J?
New retaier and no RTV around seal.
Iirc you should be able to see the little spring that is on the lip of the seal. The only way you are gonna know where it is leaking from is to pull it.

Sent from my iPhone, probably because I am bored at work.
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Unread 07-17-2013, 06:16 PM   #10
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Quote:
Originally Posted by bigbossd1030 View Post
Iirc you should be able to see the little spring that is on the lip of the seal. The only way you are gonna know where it is leaking from is to pull it.

Sent from my iPhone, probably because I am bored at work.
You sure? I thought the spring went towards the pressure side. In this case the interior of the tcase........ Maybe why mine is leaking?
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Unread 07-17-2013, 06:20 PM   #11
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Quote:
Originally Posted by Why J?

You sure? I thought the spring went towards the pressure side. In this case the interior of the tcase........ Maybe why mine is leaking?
Hmm, my output shaft at the rear has the spring on the outside. So do my axle seals. I don't think there is any pressure in there though. I could be wrong, but I don't have any leaks at all now that I fixed my power steering box.

Sent from my iPhone, probably because I am bored at work.
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Unread 07-17-2013, 06:23 PM   #12
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Quote:
Originally Posted by bigbossd1030 View Post
Hmm, my output shaft at the rear has the spring on the outside. So do my axle seals. I don't think there is any pressure in there though. I could be wrong, but I don't have any leaks at all now that I fixed my power steering box.

Sent from my iPhone, probably because I am bored at work.
Might be my issue then. I'll post up a report and pics after I get it pulled tonight.
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Unread 07-17-2013, 06:32 PM   #13
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Quote:
Originally Posted by Why J?

Might be my issue then. I'll post up a report and pics after I get it pulled tonight.
Good luck!

Sent from my iPhone, probably because I am bored at work.
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Unread 07-17-2013, 08:39 PM   #14
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So this is what I got. There was a lot of red fluid that smelled like ATF, between the trans NV3550 and the tcase NP 231.

I have no idea what color the NV3550 fluid is or how it smells.

The tcase input seal was wet up to the input gear. Also one of the seal retainer bolts was wet with ATF in the inside when I removed it. All pictured below. It doesn't appear that there is very much RTV on the seal retainer. It is pictured as it came off the tcase.

I also included pics of the input gear and the seal from the out side and inside. No idea if it was installed correctly or not.

Here are the pics.
image-4240338714.jpg

image-76457437.jpg

image-78939811.jpg

image-1626576895.jpg

image-3926279120.jpg

image-1191146488.jpg

image-1825538110.jpg

image-3675538928.jpg

image-55510743.jpg

image-2480000269.jpg

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Unread 07-17-2013, 08:56 PM   #15
bigbossd1030
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Quote:
Originally Posted by Why J?
So this is what I got. There was a lot of red fluid that smelled like ATF, between the trans NV3550 and the tcase NP 231.

I have no idea what color the NV3550 fluid is or how it smells.

The tcase input seal was wet up to the input gear. Also one of the seal retainer bolts was wet with ATF in the inside when I removed it. All pictured below. It doesn't appear that there is very much RTV on the seal retainer. It is pictured as it came off the tcase.

I also included pics of the input gear and the seal from the out side and inside. No idea if it was installed correctly or not.

Here are the pics.
So I have been trying to compare my seals I have left from my t case job I did. I only swapped the rear seals. And the only one I have that looks like it goes there has a spring on both sides. But it also has a rubber end to one face of it. I think that rubber face goes to the inside of of the t case. Yours would appear backwards if I am right. Someone is going to need to confirm this. Here is a picture of the seal. The first picture is what I believe is the outside of the case and the second is what I think goes to the inside. I think that rubber face seals in the t case groove.

Sent from my iPhone, probably because I am bored at work.
image-1744700716.jpg

image-1344649808.jpg

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