How to determine your gear ratio.

[CJ]

There are several ways to determine your gear ratio.

1. Look for a tag on the differential.
2. Pull the differential cover and look for the # of teeth stamped on the ring and pinion.
3. Count the number of teeth on the ring and pinion.
4. Lift the wheels off of the ground and count the drive shaft rotations.

1) Some diff's still have the OEM tag attached to a cover bolt. This usually gives the information you need including if the diff has Limited slip. The draw back to this tag ID is that you do not know if anyone has changed anything in the axle. NOTE: See chart below for tag information.

2) Look at the ring gear for a four number stamp such as '4111'. This tells us that we have a 41 tooth ring gear and an 11 tooth pinion gear. By dividing 41 by 11 (41/11) we come up with a ratio of 3.73 to 1. The advantage to pulling the cover is that you can inspect the diff and check what carrier type you have.

3) If there is no stamp on the ring gear you can also count the teeth on both. Follow the math example in item #2 for the ratio calculation.

4) Jack-up the rear of the Jeep. Block the front wheels and place the trans or transfer case in neutral.
Make note or mark a wheel and the drive shaft.
Start to rotate a rear wheel by hand, if the other rear wheel rotates in the same direction (this means you have a Limited slip or locking diff) - rotate the wheel one time and count the drive shaft revolutions.
If the other rear wheel turns in the opposite direction (this means you have an open diff) - rotate the wheel two times and count the drive shaft revolutions.
Your ratio is determined by the number of drive shaft revolutions.
Example - if the shaft rotates about 3 3/4 turns you have a 3.73 diff gear ratio.

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NOTE: If you believe your Jeep has the stock axles and gearing you can refer to the chart below and follow the differential tag codes for your ratio.

Remember this chart only refers to what the Jeep came with from the factory. At any point in your Jeeps 30 or so years on this earth it may have been re-geared!!!

[COLOR=black]Diff Type [B][COLOR=#ff0000]   Gear[/COLOR][/B] [B][COLOR=#ff0000]Ratio[/COLOR][/B]    Code letter    tooth count 
                                         (pinion/ring)
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standard       2.73              D           15/41
trac-lok       2.73              DD          15/41
standard       3.31              B           13/43
trac-lok       3.31              CC          13/43
standard       3.54              A           11/39
trac-lok       3.54              AA          11/39
standard       3.73              GG          11/41
trac-lok       3.73              Q           11/41
standard       4.10              C           10/41
trac-lok       4.10              CC          10/41
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