Before you tear into the rear main you need to check out other "easier" seals.
The valve cover is knows to leak and look more like a rear main leak than an actual rear main leak.
Also the oil filter mount can be a souce of a leak. Just go to the dealer and pick up the 3 o rings to mount and change them. You can see a good write up on
www.madxj.com under "engine", it an article about going to a larger oil filter.
You need to examine your block and figure out where the oil is coming from. Remember oil flows down hill, not up hill. Start at the valve cover, see if it is clean, then examine the head to see if their is oil on it from the valve cover gasket. I think you get the idea.
The bolts at the rear of the valve cover are known to become loose over time and cause oil to flow down the back of the enigne. I had a valve cover leak and replaced the factory RTV silicone with the Fel-pro gasket. I scraped off the factory gasket, applied indian head cement to the valve cover and to the gasket per the insturctions. I found out the hard way about using indian head.
If you do not apply something like indian head the gasket will seperate from the valve cover and good chance you will not get a good seal and still have a leak.
Also when you tighten up the 15 bolts use a troque wrench, the value escapes me at the moment for my 88 Xj but it is prob different than your 96. When you torque start at the center and work out to the ends in the classical pattern. I first torqued to 1/2 or 2/3 the final value then went back and toraqued to the book value. Once you have done that wait 10-15 mins and then retorque. Keep waiting and retoqueing until all bolts hold torque, then you are done.
It took me 3 rounds with the fel pro gasket to get the bolts to hold torque.
Do all of this and then see if you still have the leak. If you do then consider changing the rear main. I hear fel-pro has a 2 lip seal vs the factory 1 lip seal. If you have a groove in the crank then the second lip will ride on "fresh" surface and prevent a leak.
