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Rear Main


NAXJA Forum User
Well on my way back from Va my 88 xj 4.0,that has always leaked, started to leak oil REAL bad. Like a quart every ten miles bad. I not real for sure but I would put money on most of it to be my real main seal. How hard is one to install, should I pull the engine or just the tranny.
Neither. Even on stock vehicles, if you jack up the front end to "full droop," you should be able to slip the oil pan out without pulling the engine or the transmission. Since it's a two-piece seal, you can remove it with everything else in place - I've done it, and so have many others.

Search around for hints and tips - it's something that can be done in a day, if you buckle down. Make sure you get the later (1996-up) oil sump gasket - it will fit, and it's one-piece moulded rubber, so you don't have to wrestle with it as much as you do the four-piece cork-and-rubber version. (I know it fits - I've got one on my 88...)

As I'd said, I've covered this myself more than a few times, and I'm not going to go into it again. There are quite a few others here who will give you the same response.

Search for <rear main seal>, looking for any or all of the following usernames:
Dr. Dyno
Ed A. Stevens

And those are the ones I can come up with offhand...
Also double check that oil filter adaptor gasket. I had mine begin to let go on my way home from Charlotte one day. If the part of your oil filter that is facing the ground has new oil on it, that would indicate the oil filter adaptor.

However, a quart every 10 miles, and the fact that it's a 88, i'd have to think it would be something a little more serious, such as a rear main.

Now that I think about it, also check your valve cover gasket....those are real common to leak on the 4.0 and will mock a rear main leak (just like the oil filter adaptor will).
If you do this ... buy two or three rear main seal replacements. They are cheap and easy to mess up during installation.
Don't make the same mistake I did: I accidentally shaved some seal material off the replacement on the sharp edge of the block during installation. Consequently, the new seal did no better than the old one.
clean the pan and the block before hand. while the pan is out clean any sludge there might be inside.the rear main seal isnt brain surgery, its just very messy and time consuming. good luck
Thanks for everones help just finished up at 3:30am:wow: and it dont leak a drop now. Would had done it allot sooner if I knew it was gonna be that easy. Thanks to everyone that gave me advise.:guitar:
Hasyour oil consumption improved since you replaced the rear main?