It's Leaking It's Leaking ??

got a nice moderate sized splotch of an oily substance under the MJ confirmed upon swapping parking spots. Based on position of the splotch (technical term) directly below the tranny/driveshaft ujoint the only possible culprit is the output of the tranny? so my guess is it smells like tranny fluid (my sniffer is a little disfunctional tonight). Bad seal? This is under my MJ, specs are in my sig, and as always TIA for sharing your knowledge on the subject.

Yeah, sounds like the transfer case front output shaft seal. The fluid is tranny fluid, because tranny fluid is used in transfer cases too.

there is a plug in the yoke much like a freeze plug. sometimes they can leak seaming like the output seal is leaking.

That sounds like my problem. I've got drips coming off where the yokes join. Nothing on the transfer case or around the output shaft. Where is this plug and how do you fix it?

To clarify, My MJ is a two wheel drive, manual 4 speed tranny. On mine I havn't yet determined if it's leaking from the tranny output seal or from where the yokes join. I picked up an output seal at Autozone the other day while I was there. The computer listed it as a transfer case output seal so I hope it's right for my AX4? - If it is tranny fluid then it would be gear oil right?, I did a search and found the big gear oil controversy but no specific info for my 1987 4 speed. I'll confirm exactly where it leaks from tonight.

I havn't been driving it since I first posted this so it's time to get it done and restore my XJ to weekend only status!

MJ ax4 seal replacement, U Joint 101

So I checked (at long last) and my 2wd trans extension housing oil seal is the culprit for sure. Since this is a new lesson in Jeep mechanics for me I've read up in Haynes and Chiltons....

Haynes and Chiltons said to replace the U Joint straps each time you disc. the driveshaft, they should have these at Autozone I'm guessing?

only Chiltons said to use a "sealing compound" on the new seal. I'm not suprised both manuals didn't cover both topics, any other tips I might have missed?

Don't get the straps at 'Batozone or similar, go to NAPA. The 'zone/Advanced/Pep Boyz sell them individually in the Help! section, and they're about $4 EACH...NAPA sells them by the set for about $5
The extension housing seal is the same part description listed as for what's used on the 4X4 model trannies that goes in the back of the case where the output shaft exits (and the TC input fits inside it), so make sure it's the correct part. You might want to pull your old one and take it with you just to make sure.
Jeff

Thanks Jeff. I visited NAPA after work yesterday and got a set for $6.99.

After striking out at multiple parts stores I found a store with two of the correct seal. That part about getting it in square turned out to be a PITA. If I screwed it up at least now I know where to go get another one.

Now the fill plug! I found a big huge but very flat low profile "thingy" on the passenger side about the same size and shape as what appears to be the drain plug. Unless it's the big torx one on the driver side that appears to say "don't remove" or something! I'm totally lost here, the books I have are no help. Anybody have any pics or a very good description of the AX4 tranny oil fill plug?

THe fill plug is the one on the driver's side with the torx. It's a T45 or T50 IIRC...have fun getting the lube into the case, 'cause it ain't easy! You can use a siphon pump, or most places sell a screw-on plastic tube that fits on the lube bottle so you can tilt the bottle, but there's not alot of room under there to get the bottle high enough to let the lube flow in. A really easy way is to pop the shifter out of the top of the tranny and pour the lube in from inside the cab (just undo the fill plug and fill until it starts to seep out of the hole), but you've got to remove the bezel and dust boot to get at the shifter. Make sure you use GL3 lube, not GL5, also.
Good luck!
Jeff