How to Identify Wrangler Axles & Axle Differences

The Dana portion is the nameplate of Dana Inc., who is the manufacturer of the Jeep axles. There have been a few different axles used in Wranglers over the years with the Dana 44 being the most popular. The Dana 30 will only be found as a Jeep front axle while the Dana 35 will only be found as a rear axle on Wranglers. Dana 35 axles have earned a very poor reputation in the off-roading world, however, it is a great axle for stock Wranglers. If you intend on running 33 inch or larger tires on your Wrangler, make sure you have a Dana 44. If you try running huge tires on a Dana 35 you will probably end up snapping an axle shaft.

Each Wrangler axle has a slightly different look, making them easy to distinguish. The graphic below will show the appearance differences.

A Dana 30 cover will look like a rounded square. It should have 10 bolt holes and is 9 inches wide.

A Dana 35 cover will look like an oval. The cover will have 10 bolt holes and is 10 and 5/8 inches wide.

A Dana 44 cover is a weird shape that looks kind of like a muffin. Like the rest of the covers, you'll still have 10 bolt holes, and it's 10 and 3/8 inches wide.

Identifying the axles in YJs is pretty simple since there were no options for it. Every YJ came with a Dana 30 up front and a Dana 35 in the rear.

TJ Wranglers will have either a Dana 30 in the front and a Dana 35 in the rear unless you have a Rubicon model. In which case you'll have 44s front and back. Some TJs with a Dana 30 in the front can have a 44 in the rear as it was an option from the factory.

In early two-door JK models you may find a Dana 35 in the rear (2007 2-door models), but starting in 2008 the Dana 44 is the standard rear axle on JKs. The Dana 30 is once again at the front, but all Rubicon JKs will have Dana 44s in the front and rear.

JL Wranglers have a Dana 30 up front and a Dana 35 in the rear. The exception as always is the Rubicon (44s front and back).

Aside from the Dana differential covers, the biggest difference between the axles is the size. The number in the name (Dana 30, Dana 44, etc.) is in reference to this.

Dana 30: This axle size is the most common, and you'll only find it on the front of Jeep. They have a ring gear diameter of 7 and 1/8 inches. The Dana 30 gear ratios are either 3.21 or 3.73. The width of the axle shafts is 1.13 inches.

The YJ Dana 30 hold a reverse cut ring and pinion, but the TJs do not. Both TJs and YJs, however, use a 5x4.5 inch bolt pattern. 

Dana 35: This was an axle size used on most Jeep rear axles. They had a ring gear diameter of 7 and 9/16 inches. They came with either a 3.21 or 4.10 gear ratio. The width of the axle shafts is 1.13 inches.

Dana 44: These are the beefier axles found on the rear of all Wrangler models now with either a 3.21 or 3.73 gear ratio. The Dana 44 ring gear size is 8 ½ inches. Rubicon models come standard with a 4.10 rear gear ratio and also use a Dana 44 axle in the front with either a 3.73 or 4.10 gear ratio. The width of the axle shafts is 1.31 inches. Rubicon models also come with an electronically lockable differential for optimal traction while in 4WD. 

Keep in mind not all Dana 44s are the same. JK Rubicon models have a thicker, slightly redesigned 44. This Rubicon axle is referred to as a Super Dana 44.

• Dana 30 - 27 splines
• Dana 35 - 27 splines
• Dana 44 - For TJs, the inner and outer axle has 30 splines. JK Rubicon model front axles have 30 inner splines and 32 outer splines. The rear inner has 32.

Note: Rubicon model Dana 44 axles are not the same length as each other due to the design of the electronic lockers. The non-Rubicon model 44s are the same length.

Axle shafts with a u-joint in the center are measured from the center of the u-joint. Measuring front the center to the end of the shaft will get you the inner and outer axle lengths.

C-clip axle shafts and semi-float axle shafts are measured slightly differently than the full-float shafts. C-clip and semi-floats are measured from the end of the splines to the front of the mounting flange. Full-float shafts are measured from the end of the splines to the back of the mounting flange.

In addition to the differential covers and ring gears, the heart of an axle is the differential which mates with the splines of the axle shafts. Axle shafts are centered and held in position with the axle bearings, and they're sealed with the axle seals. The complex mating of gears and splines work in unison to transfer the power through the drive shafts to the differentials.

Fundamentally, both systems perform the same functions of providing traction to both front and rear wheels. AWD (all wheel drive) drivetrains are seen more often in sedans and sports cars. These systems are always on and constantly transferring power to different wheels through sophisticated traction monitoring. The system is better utilized during high on-road speeds.

Jeeps use a 4WD (four-wheel drive) system which is an older and more mechanical drivetrain. Normally Jeeps are rear wheel drive trucks. The driver can manually engage the transfer case to engage the front differential. The power is delivered to opposed wheels. 

In addition to manually engaging 4WD, Rubicon models have the ability to electronically lock the front and rear differentials. When engaged, the lockers will transfer power to both wheels, providing power to all wheels.

It’s important to remember a Jeep's 4WD drive train is designed to be engaged only when the wheels are slipping due to loose terrain. When engaged, the 4 low system will reduce engine speed, bringing the Jeep to a crawl. The activation of the electronic lockers provides an additional level of traction, but requires you to pay more attention to the terrain. You should only lock the diffs for brief moments to help your Jeep regain traction.

The Jeep’s drivetrain is a very complex system, but unlike AWD it's manually engaged when needed. This results in a much more durable and less complex system that mainly relies on proper gearing and power transfer. With proper use and maintenance, the system can last for a long time and provide a high level of traction when needed.