Jeep Wrangler JK 2007-2018 Gear Ratios Explained

Jeep JK 2007-2018:

This can be a confusing application if you don’t work with it every day.

Non-Rubicon- Rear axle

The 2007 model reportedly was offered with far the too weak Dana 35 axle, however, we’ve never seen one or heard of a customer that has one in this vehicle.  For the purpose of this article, we’ll concentrate only on the Dana 44 rear axle.

All gear ratios used in the JK will be of a ‘thick’ design and the 3.73↑ case.  For standard 30 spline axle shafts our RD117 will be used.  For custom 35 spline shafts the RD147 will be used.  All Air Locker cases will need to be drilled for the ring gear bolts.  Early versions (2007-08) used a 7/16” bolt and later version used a ½ bolt.

Non-Rubicon- Front axle

All front axles will be Dana 30 differentials.  ‘Thick’ gears have not been a consideration here and only axle spline count and gear ratios are a concern.  The most common Air Locker used here is our 27 spline 3.73↑ case RD100.

JK Rubicon axles- Front and rear

The front and rear Rubicon axles both utilize a factory electric selectable locker.  This locker has proven to be very problematic and it is frequently removed due to failure.  Due to the internal design of the factory electric locker, the Air Locker cannot be manufactured in a way that will allow the use of the factory axle shafts.  We offer the RD157 for this application (front and rear) and it requires special aftermarket 35 spine axle shafts.