I would say that most 1 tons come with a 4.10 rear but it could be special ordered with something else. No metal tag on the rear end case ?? You could jack the rear end up (use car stands of course) and count the number of turns the pinion yoke or driveshaft makes as compared to the tire. If its 4 turns of the yoke to 1 turn of the tire then you're in the 4 to 1 ratio.