In 03, the only ring I could find was the big one, (90, 4.0). I got insanely angry not being able to get the threads started, installing, working from above, (Mostly IIRC).
Very important you understand, you may not see it's leaking from above, you just have drips off the bell-housing and maybe smoke/smell from oil burning off the exhaust where it crosses over behind the pan.
It's plenty understandable why loads of the "under informed", have gone after their Rear Main Seal, when the adapter was the fault.
Ya gotta' really get under there and look. "knoggen poken" Cruiser calls it. Besides the actual oil leaking, you will see clean areas where the "HD", (High Detergent), oil has cleaned. It runs strait back and drips off the bell-housing. See here, this a good direction to look from.
I posted a thread about my '94 adapter. This one has a Torx recess in the "bolt", which is a hollow tube type thing, that required me to use a pipe wrench to brake it loose.
Had to jack the Jeep up to get under there & verify where the oil was dripping from. Earlier it leaked from loose bolts on the valve cover......
I washed the engine down after fixing this stuff....
So, for me today..I could get the 5/8" box on the hex bolt, but no way could I crack it. (could barely reach it). So I found my largest (handy) box/combo wrench and used that to push on the open end of the (5/8 box/combo), that was firmly seated on the OFA blot. Just pushing on the second wrench. I'm pretty strong, and it was hard, you might figure some leverage to crack that booger, just please always be sure your box wrench is solidly seated on the bolt so you don't booger it up. You can normally feel if it's right or not.
Once it cracks, here's a tip. On your back, with your feet out under the drivers side, back by the left rear wheel, you can then spin the bolt out by hand. (btw, if you are pushen 300#, getten' out from there is fun!)
FROM HERE YOU MIGHT FIND THAT O'Rylies'S KIT #82560 O ring "kit" does not contain a single O ring that fits an 87-90 Jeep. (one brown one was close, but came "pre nicked")
So I'm stranded 1/2 hr from town. I put blue RTV in the gruve's of the crucial two, will tighten the last 1/4 in the AM.
I used Felpro #70301 when I did mine. Should be the same for all years of 4.0?
It didn't come with the smaller o-rings for the shaft, but I have a 500-piece o-ring kit. I used the correct sized ones from my kit.
I doubt you would have any luck with RTV on that..................I wouldn't dare use it there.
I made my own shorter Torx socket when I did mine.
I modified it so I could put a large box-end wrench on the outside of it.
Disconnecting the passenger side motor mount and using a jack to tilt the motor up a couple inches made all the difference between an insanely difficult job and a moderately irritating job.
I had an uneventful experience doing this. knocked the bit out of a torx socket, used a 12mm wrench on it like the pic above. the bolt was tight so I hooked another wrench on the end for leverage. it's not as difficult as many want to think. Last time I did it I replaced 2 in a total of 11 minutes.
I posted this in a thread awhile back but I think its worth letting other know.
I replaced my oring in my adapter about 2 years ago after noticing a leak and then about 2 months later it started leaking again so I decided I was going to find a better solution to the problem of crappy gaskets.I was siting down in my garage trying to think of a way to fix my problem and I looked over and saw a old oil filter I had from a oil change I did in my work beater(93 Saturn SL) oil filter "Purolator L10241". I pried the rubber oring out of it and it fit right into the slot for the adapter gasket,it took some stretching and mashing but it fit good and tight so I put it all back together and it has worked out GREAT! I did have to hold the adapter in place to tighten it up until it got tight so the pin could hold it in the right spot since the gasket is really thick but I have great faith that it will last along time.
By the way its still holding up great,dry as a desert....
On mine, I couldn't keep the Torx bit in good enough ( rust ) to break the thing loose. If I ever have to do this again, I'll weld a big nut on the dam thing.
No, they change. I believe this to be creditable...but just noticed it stops at 92. Any further info would be supper! 
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