T-case leak

I have a leak out of the back of my 242 around the slip yoke of my driveshaft. I just replaced the seal, but the parts store didn't have one listed for the 242 and I compared my old seal to the one they had listed for the 231 and they appeared identical in size. The seal is properly installed, but is leaking.
I drove about 3 miles today and after I stopped it quickly made a puddle about 1 foot around and fluid was all over the rear diff where it had been leaking while driving. I think it is possible I overfilled the case, but didn't think it was possible I overfilled it that much. I later drove the return trip of 3 miles and it immediatly began to puddle again.

Anyone have any ideas on where to start on this problem?

what year 242 ya playin' with? I'm pretty sure the rear output shaft seals are the same on the earlier ones (Renix)

it is a Renix...89

The old seal should have a part# on it that can be cross referenced.

old seal was original and I didn't want to go to the stealership.

You would not have to go to the dealership, Napa or CarQuest can cross reference the part# !!

just checked the old seal and no part number is visible.

Nobody has any ideas? Do I need to change the seal or could a good seal leak if it is overfilled? Is there any reason fluid would come out of the tailcone seal if it is not overfilled?

You need to change your seal out to the 242 seal. I just put my 90 XJ in the shop for u-joint replacement and somehow they put on the 231 seal and I have the 242 case, and it started to leak. So I took back up to the shop told them I have the 242 case, and that they probably put the 231 seal on, and that it needs to be changed out, they are supposed to be doing that today free of charge.

wouldnt the seal be the same for both since the driveshaft yoke is the same size and both cases use the same size(spline count) output shaft?

89xj said:

wouldnt the seal be the same for both since the driveshaft yoke is the same size and both cases use the same size(spline count) output shaft?

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Yes, both driveshafts and tailcones appear the same. The shaft I used as a replacement was originally from a 231 t-case...so even if there was a diffrence in the diameter of the yoke it should be correct now with the seal from the 231.

From what I'm reading here it sounds like you need to get the 242 seal. If it leaks after that then you can start diagnosing things.

I don't think the seal is the issue. It has been confirmed by several others the seal and tailcone should be the same on both the 242 and 231 in the Renix years.

I just checked the fluid again and it appears to still be full. How much does ATF expand when it gets to operating temperature?

Part No.
4370N National Oil Seal Rear; New Process 242J 2 Spd. Full Time Transfer Case Warranty: Limited 2 Year*


Part No.
4370N National Oil Seal Rear; New Process 231J 2 Spd. Part Time Transfer Case Warranty: Limited 2 Year*


definitely looks to be the same--

dexron expands a whole bunch when hot-- but I'm not sure the transfer case would get hot enough

Not that I really know what I'm talking about as I don't but as an idea what are the chances of the AW4 automatic puking fluid into the transfercase? Otherwise I'd say it sounds like you overfilled it or your yoke is worn where the seal rides.

Jeepm@n said:

Not that I really know what I'm talking about as I don't but as an idea what are the chances of the AW4 automatic puking fluid into the transfercase? Otherwise I'd say it sounds like you overfilled it or your yoke is worn where the seal rides.

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Shouldn't be the case - there is a seal on the back of the trans, and one on the front of the xfer case.

The fluid expansion shouldn't be an issue, as there is a vent on the top of the case, and the case is "full" when the fluid runs out of the fill hole (pretty much impossible to really overfill).

Sounds like either the wrong seal is installed or the shaft is damaged. You said you have a SYE on the case- was it a shaft swap or a hack-n-tap of the original part?

Mark

mfascuba said:

Shouldn't be the case - there is a seal on the back of the trans, and one on the front of the xfer case.

The fluid expansion shouldn't be an issue, as there is a vent on the top of the case, and the case is "full" when the fluid runs out of the fill hole (pretty much impossible to really overfill).

Sounds like either the wrong seal is installed or the shaft is damaged. You said you have a SYE on the case- was it a shaft swap or a hack-n-tap of the original part?

Mark

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No SYE. On Sunday on the trail I broke the rear joint in the drive shaft. When I went to replace it a strap bolt broke in the diff yoke. I tried to continue with only 3 strap bolts, as I had no way to drill the broke one out on the trail, and the other 3 bolts broke about 20 feet further up the trail. I drove it home from the trail in front wheel drive and after further inspection the metal lip around the seal appeared to be damaged. I replaced the output seal on the t-case, the yoke on the diff, and used a spare drive shaft because where the joint broke it had been damaged. Now it still continues to leak. After I checked the fluid yesterday and it was where it should be, the leak remains. I know the seal is the correct one, however it appears to be defective. I will replace the seal and see if that solves the problem.

Where is the breather line on the 242? Where does the top end attach?

Breather is on the front top of the drivers side, above the drive shaft. Spring clip holds it on.

I found the problem. The seal did not fit tightly against the slip yoke. I went back to the parts store and got the seal they had listed for a 98 model (mine is an 89) and it seems to be working properly.

The new seal I got was a Timken and the part # was 4370N. I hope this helps someone in the future.

Thanks for all the help and replies.