Top Loading Double Reduction Differential

By having the center section (diff assembly) drop in from the top of the axle housing instead of the front or rear like conventional axles, this allows a few positive things to happen; 1) the driveline angles can be reduced as drive pinion is located at the very top of the differential, this also helps keep vulnerable driveline components out of the way of trail obstacles, and less likely to be submersed in mud or water. It also allows a pinion mounted brake system to be used without the risk of it being damaged. Also, with the differential being double reduction and top loading there isn't a large crown gear hanging down below the axles center line, with the proper shave kit, the ground clearance under a 2.5 Ton pan can be comparable to a dana 44.

Fully Sealed Steering and Axle Components

The 5 Ton axles run a boot that seals to the axle tube and the outside of the steering knuckle. If properly maintained, these boots will completely seal out mud, water and dust from the kingpins and axle shaft u joints, it also prevents contamination from ever entering the wheel bearings through the backside of the spindle.

Easy to Work on the 5 Ton Axles

Don't require much for specialty tools to be serviced, field jobs like changing axle shafts, bearings or seals can all be done with simple hand tools. Center chunks can be a bit more complicated to work on, but seldom require repair. Also, the square plate steel axle housings are easy to weld to and build brackets and mounts for.

Do I Need to Run Boots on My Rockwell Axles? Even If I Am in Dry Conditions or If I Run Sealed U Joints?

Yes, the Rockwell axles are designed to use knuckle boots, they prevent dust, dirt, and water from entering critical wear points like the king pin bushings, thrust surfaces on the axle shafts, u–joints, also the Rockwell axles don't use a seal inside the spindle, without the boots it is possible for contamination to enter the Hub through the inside of the spindle down the stub shaft. It is highly recommended to run one-piece silicone boots and keep them in good condition. It will help to significantly cut down on maintenance costs.

Different Versions of The Military 5 Ton Axles

There are 3 common versions of the 5 Ton military axle,
 the oldest is known as the 800 series
identifying markers on these axles is the smooth Hub and round bottom diff pan, most of these axles also came with hydraulic drum brakes, axle shafts common in these axles were the ball and claw and the cv style, the Hubs on these axles are the most desirable as they can be easily flipped to change track width same as the 2.5 Ton axle

Next newest style was the 900 series, without CTIS (central tire inflation)
these axles can be identified by the Hubs, instead of being flat across the circumference they have a dish, these Hubs cannot be flipped to change WMS like the 800 series, these axles also came with u-joint style axle shafts and air drum brakes

The last and newest version of the 5 Ton axles is the 900 series with CTIS
these axles can be identified by a flat bottom diff pan and dished Hubs with fittings for the CTIS, these axles all came with u-joint style front axle shafts and air drum brakes

Parts Interchangeability

Between the 3 versions of the 5 Ton axles there are some parts that will interchange

First off is the axle shafts, all rear shafts will interchange between the 3 different versions’ there is no difference in length or spline diameter, front shafts however are slightly different, between the 800 series and 900 non CTIS axles all the shaft will interchange without any issues, including ball and claw, cv and u-joint styles, only problem is when you try and change shafts between the 900 CTIS axle and the older 900 and 800 axles, the problem lies in the inner axle tube seal, the newer CTIS axle shaft has a larger seal surface on the inner shaft as all the other versions, meaning the shaft wont fit in the smaller older axle tube seals, however we do offer a conversion seal that will allow you to install the newer shafts in the older axles

5 Ton Hubs all 3 versions of the 5 Ton Hubs cam be swapped between the various axles, you will need to keep the bearings with the appropriate axle, for example if you go to uses a 5 Ton CTIS Hub on a 800 non CTIS rear housing you will need to use the 800 bearings in the CTIS Hub, same goes with the seals, one more thing to mention is the 900 CTIS axles use a smaller sized spindle nut that will not work on the older non CTIS spindles

The majority of 5 ton axles all come with open differentials, there were a few versions that had air lockers and are commonly knows as a 7ton, also the military had a few versions of rear axles that came with a Detroit locker, there are no real identifying marks the best way to know for sure if you have an axles with a Detroit is to hold 1 hub while you spin the other 


military ratio is 6.44

  • Front axle no brakes 1250lb 
  • With brakes 1650lb

5 Ton axles have 2” diameter axle shafts 

Bolt pattern: 10x 285mm, is the same as most medium/ heavy highway trucks

WMS with Hubs Flipped out:

  • Front: 87.5"
  • Rear: 83.25"

 M923 A2 Driveshaft Lengths

  • Front Diff to T-Case: 71"
  • T-Case to Transmission: 22"
  • T-Case to Rear Front Diff: 24-3/4"
  • Front Rear Diff to Rear Rear Diff: 32"
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