if you can't read the tag, you can use this procedure:
-jack up one rear tire,
-put trans in neutral,
-rotate tire around exactly twice while counting the number of times the driveshaft rotates,
- that number is your ratio. 3 and a half times = 3.55/3.54 just over 4 times is 4.10/4.11
if it has a posi in the rear, then jack up both tires and rotate around only once.