2003 Toyota Tundra are the ring n pinion gears the same on a 2 wheel drive n a 4wheel drive

Couple of options to determine differential gear ratio .. Call dealer with vehicle id number .. BEST > Count the number of teeth on the bigger ring gear then count the number of teeth on the smaller pinion gear and divide small number into big number for the 'exact' gear ratio... **Conspicuously mark one of the teeth on each gear so you do not loose count!!** .... You can pretty much bet the two diffs will not have the same gear ratio!