I've wondered about that....how much lubrication do the side and spider gears need?In 2H the ring and pinion don't turn because of the FAD, but you do have movement in the driver axle, passenger inner stub axle, and the side and spider gears inside the differential. Bad things will still happen in 2H without gear oil.
I always think of the gear oil as mostly protecting the r&p, carrier and pinion bearings.
I'd like to see a torture test of what exactly damage would occur in the JL setup. I'm not saying it'd survive just fine, I'm just curious