How do I verify my rear end gear ratio?

Have you ever wondered how to manually check what gear ratio your vehicle is equipped with from factory? Finding this information is easier than you may think!

Most cars and trucks will have this written on the door jam with the VIN and build information.  If not, you can use this method:

1. Block the front wheels so that they cannot move.
2. Jack the rear of the car up so that the rear tires are off the ground.
3. Put the vehicle in neutral (but not running).
4. Mark the driveshaft somewhere you can see it from a safe area.
5. Rotate the rear wheel towards the front of the car one full rotation while watching how many times the driveshaft turns.

• 2 ¾ rotations = 2.73 gears
• Just past 3 rotations = 3.08 gears
• 3 ¼ rotations = 3.27 gears
• 3 ½ rotations = 3.55 gears
• 3 ¾ rotations = 3.73 gears
• Just under 4 rotations = 3.90 gears
• Just past 4 rotations = 4.10 gears

If you are having trouble determining the ratio, you can always call the car or truck's manufacturer's customer service phone number and provide the VIN; with this information, they will be able to tell you what the factory equipment was for the vehicle.