According to Marti report, it’s a 3.50 open differential. Really need to check to see what is REALLY there, as the PO may have changed the gears. If the gears are indeed 3.50s, I’ll more than likely go to 4.11 or 4.38s as the 37.5” tires will not be nice to the clutch. Had 9.00 X 16 militarys on the previous Bronco, but it came with 4.11s and it ran them okay.
Randy