Output seal leak

Was doing an oil change today and noticed that the output seal on my xfer case was leaking horribly, how hard is this to change? WIll the case need to be dropped?

This is on a 90 XJ, 4.0 5spd & command trac 4wd.

Drain transfer case

Remove rear driveshaft

Use hook to remove output seal.

Use small hammer to tap new seal into place.

Lightly grease slip yoke on driveshaft and reinstall. USE LOCTITE on the bolts, and I also tend to replace the bolts with 1/4"-28x1" socket head capscrews (easier to work with, and stronger.)

Refill transfer case.

Drive off happy.

Timken #2506 for NP231 (easily verify model of transfer case above or below - there's a 2"-ish round silver tag opposite the front output shaft, or the shift bezel will read "2HI - 4HI - N - 4LO" for the NP231. If you have the NP242, you will have "2HI - 4FT - 4PT - N - 4LO" on the bezel, but I think they're the same seal. Me Timken catalogue don't say.)

5-90

Thanks, it's the NP231. In order to pull the driveshaft I need to undo the u-joint at the rear axle, then pull and it will come out of the case, right? Then pull off the conical shaped thing on the back of the xfer case and put it new seal? What fluid should I be using, Dextron 2, Mopar Quadra-Trac?

Also, what would be the danger of driving with tthe fluid low? I won't be doing any wheeling soon so it should be staying in 2wd.

You don't even need to pull the tailcone - once you have the driveshaft out (it does just pull out,) you have enough access to the seal to change it. If you pull the tailcone, you have to reseal it (RTV) as well - why bother?

Use Dexron II/III fluid - that's what the manual calls for. You should need a 1-3/16" wrench or socket to get the drain plug out.

As long as the pump in the case can pick up fluid and you don't drive around that way too long, I'd think you should be alright.

5-90

5-90 said:

Use Dexron II/III fluid - that's what the manual calls for. You should need a 1-3/16" wrench or socket to get the drain plug out.

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The CORRECT size socket is a 30mm...if you can get a wrench on it, your more skilled than i am....MAYBE a thin-walled box wrench but i doubt youll be able to get any torque on it with a regular combo or adjustable.

Anywho, just drop your rear driveshaft and pop that seal out. Your supposed to use a seal puller to get it out, but a flathead screwdriver works just as well. Get a QUALITY seal...dont go with the cheapest autozone brand you can find or else youll still get leaks...i went through 4 different bands of seals before i found one that didnt leak(Federal-Mogul available at any Advance or Napa). Use a thin bead of RTV on the outside metal part of the seal and GENTLY tap it into place using a rubber mallet being careful not to hit the rubber or bend the metal flange. Fill 'er up with Dex II/III ATF and take it for a spin. If possible, park on an upwards incline and see if it leaks...if it doesnt, you should be good to go.

DO NOT drive with low fluid(again, ask me how i know) or your just begging for burnt bearings or other catastophic failure!! It holds something like 1.5 quarts of ATF...you could probably get away with running as low as a single quart, but why risk it??

CORRECT is whatever works. 1 3/16" works for both fill/drain plugs on NP 231. My RENIX XJ is the only vehicle I've ever owned that is SAE and metric, seemingly at random. The love child of AMC-Renault.

Thanks for the help guys, here's what I'm seeing:







That's from the output seal, right?

Im gonna say thats a big 10-4!! Make sure you REALLY clean off the corrosion and other junk on your slip-yolk or else your going to be replacing that seal in no time again...a peice of scotch bright works well, just clean it enough to where it looks fairly clean and smooth.

Man, you drive that thing in the ocean??

Jeffro600 said:

Man, you drive that thing in the ocean??

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I did once but never went above the tread. Lately it's just been swamps & creeks...