It's very difficult to tell the difference between a 4.11 and a 4.56 unless you do a few things to get a more accurate count of driveshaft turns. Here's how I'd go about it:
Jack up one rear wheel, and turn the wheel, not the driveshaft. The differential gears will double the wheel speed, so one turn of the rear wheel will result in approximately 8 1/4 turns of the driveshaft for the 4.11, or slightly over 9 turns for the 4.57 gear. A 5.14 ratio (which is probably what a 1 ton will have) will result in slightly over 10 turns of the driveshaft to one turn of a single rear wheel.
