Renamed for you, I hate autocorrect :thumbup:
The transmission output seal is 8350 3108 from the dealer (some parts houses can cross-ref this) and the transfer case input seal is actually different depending on what exact transfer case you have. It is J535 9457 with an 87-90 A/B/C case or 4167 929 with a 90 K case.
"A" cases: transfer case tag has part number 5300 3927, 5300 4271, 5300 4272, 5300 4301, 5300 4328, 5300 5355, or 5300 5382. All in XJ/MJ vehicles with transmission serial numbers up to 131163.
"B" cases: tag has part number 5300 6094, 5300 6095, 5300 6096, 5300 6191. XJ/MJ transmission serial numbers up to 131163.
"C" cases: tag has part number 5300 6093, 5300 6095. XJ/MJ transmission serial numbers up to 131163.
"K" cases: tag has part numbers 5300 8207, 5300 8208, 5300 8209, 5300 8210, 5300 8211, 5300 8212. XJ/MJ transmission serial numbers up to 131163.
Other wonky splits based on transmission serial number are different if it's out of a YJ, and there's no real mention of what happens if it's a transmission serial number 131164 or higher. I Blame AMC.
Oh, and there's about another half dozen lettered transfer case variants (D-J and L-O) that were used in other combinations. I'm glad Chrysler took over, the 91 and later parts application info is nowhere near this confusing. It lists applicable transfer case part numbers right in the same line as the part you're looking at and none of it depends on serial numbers of other parts in the vehicle.
I'm guessing this all has to do with the 21 to 23 spline changeover or long vs short NP231 input gears but I'm not sure why that would affect anything with an AX15, since I was pretty sure all AX15 vehicles were 23 spline even in the late 80s.
If you go with a local parts house instead of buying it through the dealer, and there are more than one option available for the transfer case input seal, I strongly recommend buying both as they're fairly cheap. Use the one that fits, return the other. Also, if you go with a local parts house for the transmission output seal, make sure to say it's for the 4x4 adapter housing, NOT anything about the transmission output, or the parts counter monkey may get confused and give you a rear output seal for an NP231 instead. Don't ask how I know this... if you want to double check, just make sure it doesn't have a metal shell around it, the AX15 rear output seal is just a little rubber/plastic one with a few lips instead of having a metal outer shell that presses into something.