Have you tried jacking up each end of the vehicle and turning the wheel by hand and counting the revolutions that the driveshaft makes, in order to determine the gear ratio? That's what I would do, instead of guessing, particularly since it started doing this about the same time that someone else was working on the axles.

1977 CJ-7, fiberglass body, AMC 360 w/ headers, DUI ignition, Edelbrock intake and Holley 4150 carb, TF999, Dana 300, 4.56 gears lockers, York air comp, 4" susp lift, 2" body lift, BFG 35" M-T tires, Megashifter, AGR pump & box, REP8000 winch.