I was driving on monstrously huge 30" BFGs (and balding ones at that). :D
I wouldn't let it bother you, just keep the fluid level up. And don't see it as a busted trans, think of it as an *opportunity* for an upgrade. :D The nv-3500 is certainly stronger than the AX-15, but the AX-15s are much more abundant.
Jeep on!
--Pete