Hi all. I've been reading older posts and found answers to a couple problems I am hiving. Seems like there is some real knowledge on this site.

I have a 1992 K2500 pickup that has a 454 and 4L80E with 188,000 miles. The tranmission was replaced with a factory rebuilt at 77,000 miles. So I have about 111,000 miles on the tranny.

Last year the tranmission started leaking right after I had a flex plate installed backwards (I know...it can't be done, but it was) after having rear mains replaced. The pin head that put the flex plate in backwards also broke the tabs on the internal wire harness that hold the plug in place. That plug is currently held in place by permamgasket and needs to be replaced properly.

Shortly after that it began leaking from the output shaft. I replaced the output shaft seal twice. Both times the leak re-appeared within a month. I took it in to my regular mechanic and had him replace the shaft seal thinking maybe I was doing it wrong. But how could you do such a simple job wrong? Sure enough..it started leaking about a month later. Last time I had a transmission shop replace the seal. And it is now one month later and I have a couple drips of tranny fluid on my drive way coming from that seal again.

I asked the transmission shop to replace the bushing in the output shaft and he scratched his head and gave me one of those looks a mechanic will give to an idiot customer who has no clue what he's talking about. I stood my ground and told him I wanted a new bushing! His boss called me later that day to tell me there is no bushing in the output shaft and that the seal that was on there was the wrong size. I accepted that. Now I have another leaking output shaft seal.

It seems like a simple thing to fix. Am I building up pressure and spittin it out the output shaft seal? Is the spline not lining up the shaft? Any ideas what to lolok for?

This truck is used primarily for off road adverntures in the Nevada dessert. It sits in my driveway all week, waiting for the weekend warrior to arrive and beat it up. It's not a pretty truck. But it has drug elk and deer out of the woods and been a great camping truck.

Thanks,

Nate

is this the transfercase rear seal you are talking about? if it is there is a bushing in the extention housing of the case that wears out that is around the slip yolk also check to see if the oil is leaking out the steel plug in the back of the slip yolk behind the ujoint.

Do you have a 4X4?

This is a 4x4. The leak is from the extension housing of the transmission where the driveshaft yoke fits into the extension housing.

No leaks from the transfer case. The fluid that leaks out is transmission fluid.

Thanks,

Nate

?????
The driveshaft yoke fits into the transfer case on a 4X4. If your talking abaout between the transmission and transfer case, then there is a gasket there that seals the 2 together. Both the transfer case and transmission use ATF. Need a better description of your leak.

Leak could be coming from inside driveshaft yoke in which case you need an o ring inside the housing. Not sure wether you have one there or not. If the leak is in fact between seal and extension housing, you then have a damaged housing. Possibly a worn out yoke.
mike

Sorry...I was confussed again. The seal I am talking about is the extension housing seal of the transfer case. When I said the transfer case is not leaking, I was thinking of the front drive shaft going into the transfer case. My leak is where the rear drive shaft fits into the extension housing of the transfer case. The seal is booted and the fluid is dripping from the rubber boot. It seems like this seal is designed to keep things out, not in.

Thanks for all the input.

Nate

is this the transfercase rear seal you are talking about? if it is there is a bushing in the extention housing of the case that wears out that is around the slip yolk also check to see if the oil is leaking out the steel plug in the back of the slip yolk behind the ujoint.

It is definately leaking from the seal. I can see it dripping from the rubber boot on the seal. If you replace the seal, it stops leaking for about a month.

How would you replace the bushing if that is the problem? Do you simply drive the old bushing in and drive the new bushing in, leaving the old one to spin on the shaft? Or do you disassemble the transfer case to get in there and do it right? I can't find any information on repairing this animal...anywhere!

Thanks,

Nate

There is a chance that your bushing is worn. Which t-case do you have? Most likely your leak is due to surface rust or irregularities on the slip yoke. Whenever I replace a rear seal I always polish the sealing surface of the yoke with some 600 grit emory cloth and WD-40. Most seal leaks are nothing more than a lip or some surface rust on the sealing surface. I would check the yoke first and try polishing it like I stated earlier and see if that helps, I've stopped more than one by doing nothing more than cleaning them up.

I am not 100 % sure, but I think I have the NP 241.

I used steel wool to clean the slip yoke the first time I replaced the seal. I did not ask the mechanic if he did. I'll be sure to clean it up reeal good this time around.

I've located some info on this T-Case and it seems relatively simple to remove the extension housing and take a look inside. Even if I have to remove the T-Case, I don't think it would be hard to completely rebuild. Might want to get in there and replace the bearings too. We'll see how energetic I get after deer season ends. Right now it is only leaking a few drips when I park it for a week or so. The level never gets low. So I think I am OK to take it off roading.

Nate

I checked and yours is a NP241. They are very simple to build if neccesary. Most likely all you would need to do is remove the 3 bolts that hold the rear extension housing on to get that off. I'm not sure if you can get a new bushing for it or not, but you should be able to from GM. They are normally fairly cheap, and with the housing off easy to replace.

I'm going to the transmission parts supply store today to pick up my ATSG guide for the 4L80E this afternoon to be sure, but I do believe you are right about the bushing being easy to replace. I found three websites that walk you through the process of rebuilding the NP241. Not one of them mentions replacing the bushing. But they do all mention replacing the bearing and carrier, which looks to be inside the t-case, not inside the extension housing.

It looks like it could go either way...but I am hoping you are right...and I want to believe it! LOL

Thanks,

Nate

I was doing some checking over at gmpartsdirect and that bushing is under $3 list and the part number is 6260048 (http://www.motorplace.com/flow-pcx/parts_catalog_components.cgi?1130907748734#).

first thing I would do is try to move the yoke up and down in the t-cace there should be very little movement. if there is slop it is the bushing. next thing is to make sure the seal (not the gasket) between t cace and trans is good. you can tell this if your trans fluid is going down with no leaks. it can leak into t case causing it to leak from being to full. if you take out the fill plug and fluid comes out it is too full.

first thing I would do is try to move the yoke up and down in the t-cace there should be very little movement. if there is slop it is the bushing. next thing is to make sure the seal (not the gasket) between t cace and trans is good. you can tell this if your trans fluid is going down with no leaks. it can leak into t case causing it to leak from being to full. if you take out the fill plug and fluid comes out it is too full.

That is definately something I have not thought about. And it makes more sense. I have zero play in the yoke, which makes me think the bushing is fine. The leak usually occurs after the truck sits in the driveweay for a week or two (this is my weekend warrior truck...I have another daily commuter truck that gets used..well..daily). If it is sitting in the driveway and the tranny is leaking into the transfer case, I can see where it will start dripping from being overful.

Thanks...you may have hit on something here!

Nate