Okay, I got caught!
I thought I had a Dana 35 rear and ordered a replacement pinion seal. When it arrived, it looked way too small. After some extensive Googling, i eventually found my Jeep's original build sheet, and it has a Dana 44/226M rear axle fitted! Interesting, because it does not "look" like the Dana 44 in the identification pictures I've seen.
The correct pinion seal is now on order. (Anybody need a Dana 35 seal??
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Taking a longer term view, I eventually want to put in an Eaton TrueTrac. Do all Dana 44's have 30-spline axles?