Rebuild of Dana 44 FBJ: Front Axle - Auto Locking Hubs
1983 Dodge Ramcharger
For Dana 44 FBJ Axle
The last phase of the project is replacing the axles, the spindles, the rotors, and the hubs. In order to replace all of the wear items, it is necessary to buy a small parts kit for the hubs. Unfortunately, this requires purchasing some parts that don't require replacement, such as some fasteners, etc.
On each front wheel, there is a hub with a cover held in place by torx style screws. Beneath this cover is a clever little geared device which, when the axle inside it turns in the drive direction, locks the rotor to the axle and causes the front wheels to pull the vehicle along with the rotating axles. While these hubs may be inadequate for mondo rock crawling with very large diameter tires, they have proven more than adequate for moderate wheeling and 31 inch tires.
Once the cover is removed, hub slides out. Behind the hub, within the rotor, one can see the rotor splines and the axle splines. Behind that is a retaining ring. This retaining ring holds in place a locking nut, which in turn holds the wheel bearings (and rotor) in place. In order to remove the rotor and the axle shafts, one must first remove this retaining ring and locking nut. Next, the rotor can slide off the spindle, revealing the wheel bearings inside the rotor.
With the rotor removed, the spindle is ready for removal. Once the spindle is off, the aforementioned work on the differential can proceed. Then, once the differential work is complete, the axles are replaced, and the spindles and bearings and seals are returned, and the wheel bearings and seals are replaced before replacing the rotor onto the spindle.
The key trick to reassembly is the tension on the locking nut which holds the rotor and wheel bearings in place. A lack of tension allows the rotor to wobble, and causes wear or failure. An excess of tension (torque on the tool used to tighten the locking nut in place) causes excess friction and wear on the bearings. A small retaining clamp is used to keep a snap ring in place, which in turn prevents the locking nut from gaining or losing tension.
Once proper tension is established and the retaining assembly is in place, the hub can be replaced into the rotor. Finally, then, the hub cap can be returned to its position. Final reassembly includes replacing the brake caliper.
Once Phase II of the project was complete, the Old Gray Mare nearly had a complete new drivetrain. Every worn bearing and U-joint had been replaced, and both axles rebuilt. The only remaining drivetrain slop (the transmission has only about 50,000 miles on a rebuild) is in the transfer case, which still has the original miles (nearly 350,000). While 3.55 gears won't win any rock climbing contests, this seasoned old SUV still hauls the family to camping trips and some worthwhile moderate off-roading. The rebuilt axles and 3.55 gears have made a considerable improvement.
NOTE: On the NP208, speedometer adjustment is easy. The speedometer gear is marked with a number of teeth. More teeth correct for a lower gear. For example, in this project, a 28 tooth speedometer gear was present with 3.21 gearing. Changing 10% to 3.55 gears required 10% more speedometer gear teeth, so a 31 tooth speedometer gear was fished out of a box of old gears which Wes Mohr had in his shop. The 31 tooth gear allows correct speedometer readout for the new gears.
This page was last modified on 29 Oct 99