If the rear differential cover has never been removed or the cover has been removed,but the owner reinstalled the tag,a tag is held to the differential cover by one of the cover bolts.The tag should have 1 number/letter/ two numbers together with no spaces. Example: 3L27 This combo stands for 3:27 w/ limited slip (trak loc).....2L73= 2:73 limited slip.The only problem with this is,if the gears were ever replaced by the previous owner with a lower gear set,the tag wont be valid.So jack the rear of the car off the ground,draw a mark on the center of the driveshaft (facing the driver side) draw a mark on the rear driver tire sidewall.Slowly rotate the wheel one complete revolution while watching the driveshaft.Count the number of revolutions the driveshaft makes during one revolution of the wheel.If the driveshaft makes 4 1/4 revolutions,that equals a 4:10 gear.If it makes 3 1/2 revolutions,that equals a 3:55 gear.If the cover is removed for any reason,you can also id the gear ratio by counting the number of teeth on the ring gear and the pinion gear & divide the ring gear number by the pinion gear number to give you your answer.So 41 ring gear teeth ÷ 15 pinion gear teeth= 2.73 gear
91 LX 342ci (10.5:1)
TFS 190cc (stage ll)
GT40 (tubular) intake
Weld ProStar XP's
Last edited by wbrockstar; 08-05-2019 at 07:45 AM.