Locking Hub - Auto

This procedure covers the removal and replacement of the automatic locking hub assembly on the front axle of a 2007 Ram 3500 with the AAM 9.25 front axle.

Warnings

Tools required

Parts

• Automatic locking hub assembly × 1 — Use OEM AAM/Dodge specification
• Hub seal (if damaged) × 1 — Use OEM specification
• Hub bearing retaining nut (if damaged) × 1 — Use OEM specification
• Shop rags × 1 — Generic

Fluids

• 75W-90 synthetic gear oil — 0.5 qt

Preparation

1. Park vehicle on level surface and apply parking brake
2. Place wheel chocks behind rear wheels
3. Loosen front wheel lug nuts while vehicle is on ground (do not remove)
4. Raise front of vehicle with floor jack and support securely on jack stands at frame rails
5. Remove wheel and tire assembly
6. Clean outer hub area and spindle with brake cleaner to prevent contamination

Procedure

1. 1

   Remove hub cover bolts
   Locate the six bolts securing the automatic locking hub cover to the wheel hub. These are typically 10mm or 12mm socket head bolts arranged in a circular pattern. Remove all six bolts and set aside. Note the location of any alignment marks or dowel pins.
2. 2

   Remove locking hub assembly
   Carefully pull the automatic locking hub assembly straight out from the wheel hub. The assembly may be tight due to the seal and may require gentle prying with a flat blade screwdriver at the pry points (if equipped) or tapping with a rubber mallet. Be prepared for gear oil to drain from the hub area - position drain pan to catch fluid.
3. 3

   Inspect hub components
   With the locking hub removed, inspect the axle shaft splines, hub seal, and bearing surfaces for wear, damage, or contamination. Check the snap ring groove on the axle shaft for damage. Inspect the removed hub assembly for cracks, worn gears, or damaged seals. Replace any components showing excessive wear.
4. 4

   Clean mounting surfaces
   Use brake cleaner and a wire brush to thoroughly clean the wheel hub mounting surface where the locking hub seats. Remove all old sealant, dirt, and debris. Clean the axle shaft splines and snap ring groove. Ensure mounting surface is completely clean and dry before proceeding.
5. 5

   Inspect and verify snap ring
   Check that the snap ring is properly seated in the groove on the axle shaft. If the snap ring was removed or is damaged, install a new snap ring ensuring it is fully seated in the groove around the entire circumference. The snap ring retains the hub assembly on the shaft.
6. 6

   Install new locking hub assembly
   Align the new automatic locking hub assembly with the axle shaft splines. Ensure any alignment dowels or pins are properly positioned. Push the hub assembly straight onto the axle shaft until it seats fully against the wheel hub face. You should feel the internal components engage with the snap ring. Verify the hub is fully seated with no gaps.
7. 7

   Install hub mounting bolts
   Install all six hub mounting bolts finger-tight first to ensure proper alignment. Apply medium-strength thread locker to bolt threads if specified by manufacturer. Tighten bolts in a star pattern (crossing pattern) to ensure even seating. Since no verified torque specification is available for this platform, do not guess a value. Obtain and apply the exact torque specification from the AAM/Dodge service manual for this fastener before final tightening.
8. 8

   Check front differential fluid level
   Since gear oil was lost during hub removal, check the front differential fluid level. Locate the fill plug on the front differential housing (driver side, upper portion). Remove fill plug and verify fluid level is at the bottom of the fill hole. Add the OEM-specified gear oil (verify exact viscosity/type in the service manual for the AAM front differential) as needed until fluid reaches the fill hole opening. Reinstall fill plug.
9. 9

   Test hub engagement
   Before reinstalling the wheel, manually rotate the hub and test the automatic locking mechanism. In 2WD mode, the hub should spin freely. Engage 4WD (ignition on, transfer case in 4WD) and verify the hub locks - you should feel resistance when attempting to rotate. Return to 2WD and verify hub unlocks and spins freely again.

Reassembly

1. Reinstall wheel and tire assembly onto hub
2. Install lug nuts and tighten in star pattern while vehicle is on jack stands - finger tight plus 1/4 turn
3. Lower vehicle to ground and remove jack stands
4. Perform final lug nut torque to manufacturer specification (typically 135 ft-lbs for this vehicle) in star pattern
5. Repeat entire procedure for opposite side if both hubs require replacement

Verification

• Test drive vehicle and verify 4WD engagement works properly - hub should lock when 4WD is engaged
• Listen for any abnormal noise from hub area during operation in both 2WD and 4WD modes
• Check for gear oil leaks around hub assembly after test drive - inspect after vehicle has been parked for several minutes
• Verify hub spins freely in 2WD mode and locks firmly in 4WD mode
• Recheck front differential fluid level after test drive and top off if necessary

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