Gear ratio

How Can I Find The Gear Ratio Of My Xj by codes or tags

Search this site for general XJ factory info or Google it. Usually you can find out based on what package your XJ is. Towing will have a certain ratio, the 4-cyl will have its own, etc.

This is not 100% accurate...but should be right for MOST XJ's 1987+


4.0L stick 3.07's
4.0L auto 3.55

2.5L stick (5 spd) 4.10's
2.5L auto 3.73 (not 100% sure on thisone as there a 3 and 4 spd autos for certain years)

The dealership parts dept can enter your VIN into the system and get the build sheet from Jeep with a listing of all your options, including axle ratio. Early XJ's have a factory option sheet behind the drivers door trim panel. The tag on the axle (if it's still there) gives the ratio. Open the diff and count the gear teeth, divide the larger number by the smaller number.

Axle Ratios-

3.07 - used with 4.0L engine / manual transmission
3.31 - only available on older (pre87?) 2 door XJs with "Fuel Economy" package
3.55 - used with 4.0L engine / automatic transmission
3.73 - found in some XJs with the towing package
4.10 - used with 2.5L engine usually, and older XJs with the "Off-Highway Vehicle" package.
4.56 - rare but can be found on some older (~ 89 ~) models with 2.5L engine and auto transmission