- Vehicle Identification Number (VIN)
- Jack stands
- Lug wrench
- Tape measure
- Chalk
- Flashlight
- Shop manual or online resource for your specific vehicle.
2. Prepare your vehicle.
- Park your Jeep Wrangler on a level surface.
- Engage the parking brake.
- Loosen the lug nuts on the front and rear wheels, but do not remove them.
- Raise the front and rear of the vehicle using jack stands.
- Remove the lug nuts and wheels.
3. Locate the differential.
- The differential is located in the center of the axle housing, between the two wheels.
- It is usually covered by a metal cover or housing.
4. Remove the differential cover.
- Place a drain pan under the differential to catch any leaking fluid.
- Use a wrench to loosen and remove the differential cover bolts.
- Carefully remove the cover and set it aside.
5. Count the teeth on the ring gear and pinion.
- The ring gear is the large gear inside the differential housing.
- The pinion is the smaller gear that drives the ring gear.
- Use a flashlight to see the teeth on the gears.
- Count the number of teeth on the ring gear and write it down.
- Count the number of teeth on the pinion and write it down.
6. Calculate the gear ratio.
- Divide the number of teeth on the ring gear by the number of teeth on the pinion.
- The resulting number is the gear ratio.
7. Reassemble the differential and reinstall the wheels.
- Install a new gasket or sealant on the differential cover.
- Replace the differential cover and tighten the bolts.
- Add differential fluid until the fill hole is full.
- Reinstall the wheels and lower the vehicle.
- Tighten the lug nuts.
