Or if there's no tag on the rear cover to tell for sure take the cover off. Count the number of teeth on the ring and on the pinion gear. Divide those numbers and that's your ratio. Ex. 30 teeth (ring) divided by 10 teeth (pinion) = 3.00 to 1 ratio. 37 (ring) divided by 10 (pinion) = 3.70 gear set.
BUILT FORD TOUGH