Front Differential

This procedure covers the removal and installation of the front differential assembly on a 2007 Ram 3500 with 5.9L Cummins diesel and 4WD.

Warnings

Tools required

Parts

• Front differential assembly (if replacing) × 1 — Use OEM specification
• Front axle tube seal (right) × 1 — Use OEM specification
• Front axle tube seal (left) × 1 — Use OEM specification
• Differential cover gasket × 1 — Use OEM specification
• Differential mounting bolts and washers × 1 — Use OEM specification
• Driveshaft U-joint straps/bolts × 1 — Use OEM specification

Fluids

• 75W-90 synthetic gear oil — 3.5 qt

Preparation

1. Park vehicle on level surface and engage parking brake
2. Chock rear wheels securely
3. Raise front of vehicle and support on jack stands at frame rails behind front axle
4. Remove both front wheels for easier access
5. Allow differential to cool if vehicle was recently driven
6. Position drain pan under front differential
7. Clean exterior of differential housing to prevent contamination during service

Procedure

1. 1

   Drain differential fluid
   Remove the differential cover drain plug (if equipped) or remove the lower differential cover bolts and loosen the upper bolts to allow the cover to tilt and drain. Allow all gear oil to drain completely into the drain pan. If removing cover, carefully break seal with pry bar and remove cover completely.
2. 2

   Disconnect front driveshaft
   Mark the orientation of the front driveshaft yoke to the differential pinion flange with paint or punch marks. Remove the four U-joint strap bolts or flange bolts connecting the driveshaft to the front differential. Support the driveshaft and carefully lower it away from the differential, securing it with wire to prevent damage.
3. 3

   Disconnect axle shafts
   The front axle on this vehicle is a solid beam axle (AAM 9.25) with the differential integral to the axle housing. There are no separate CV axle shafts to disconnect. If servicing internal differential components, remove the axle shafts from the axle tubes by removing the wheel hub/unit bearing and sliding the shafts out, supporting them to avoid seal damage.
4. 4

   Disconnect differential breather tube
   Locate the differential breather tube mounted on top of the differential housing. Disconnect the breather tube from the differential housing by removing the mounting clip or bolt. Ensure the tube is clear of the differential during removal.
5. 5

   Remove differential mounting hardware
   The differential carrier on this AAM 9.25 solid front axle is integral to the axle housing and is not a separately removable bolt-on assembly. To service the internal gear set (carrier, ring gear, pinion), work through the differential cover opening after removing the axle shafts, or remove the complete front axle assembly from the vehicle.
6. 6

   Support and lower differential
   This vehicle uses a one-piece solid axle housing; the carrier does not drop out from the axle tubes. To remove the entire front axle assembly, support it with a suitable jack, disconnect the track bar, control arms/leaf spring U-bolts, steering linkage, brake lines, and ABS wiring, then lower the complete axle. Otherwise, service internal components through the cover opening.
   ⚠Ensure the transmission jack is stable and the differential is balanced before fully removing mounting bolts. The assembly can shift unexpectedly.
7. 7

   Remove differential from vehicle
   Once the differential is lowered sufficiently and clear of all mounting points, carefully roll the transmission jack out from under the vehicle. Inspect the axle tube seals at the differential housing attachment points and plan to replace them during reassembly.
8. 8

   Inspect and prepare for installation
   If servicing the ring and pinion, transfer or replace internal components as required and set up backlash and pinion preload per spec. Clean the axle housing and differential cover mating surfaces thoroughly. Inspect axle tube inner seals and the pinion seal, and replace if worn or damaged.
9. 9

   Install differential assembly
   Position the differential assembly on the transmission jack and carefully raise it into position. Align the differential with the axle tubes and mounting brackets. Guide the pinion through the mounting area while tilting the differential as needed. An assistant is highly recommended to align mounting holes.
   ⚠Take care not to damage axle tube seals during installation. Apply a light coating of gear oil to seals before mating surfaces contact.
10. 10

    Install mounting hardware
    Install all differential mounting bolts and washers finger-tight first to ensure proper alignment. Once all bolts are started, tighten in a cross pattern to ensure even seating. Torque mounting bolts to manufacturer specifications (specifications not available in database - refer to factory service manual).
11. 11

    Reconnect axle shafts
    Reinstall the splined axle shafts into the axle tubes, engaging the splines with the differential side gears. Reinstall the wheel hub/unit bearing assemblies and torque the hub fasteners to specification (refer to factory service manual).
12. 12

    Reconnect front driveshaft
    Align the front driveshaft to the differential pinion flange using the alignment marks made during disassembly. Install the U-joint strap bolts or flange bolts and tighten in a cross pattern. Torque to manufacturer specifications (refer to factory service manual). Ensure driveshaft rotates freely without binding.
13. 13

    Reconnect breather tube and fill differential
    Reconnect the differential breather tube to the housing and secure with mounting clip or bolt. If differential cover was removed, install new gasket (or apply RTV gasket maker per manufacturer instructions) and reinstall cover with all bolts. Using a gear oil pump, fill the differential with approximately 2.5 quarts of 75W-140 synthetic gear oil through the fill plug until oil reaches the bottom of the fill hole (verify exact capacity and spec against the factory service manual).

Reassembly

1. Reinstall front wheels and torque lug nuts to specification
2. Lower vehicle to ground
3. Check differential fluid level after vehicle sits level for 5 minutes, top off if necessary
4. Verify all fasteners are properly torqued
5. Check for any fluid leaks around cover, axle tubes, and pinion seal

Verification

• Start engine and engage 4WD system to verify proper operation
• Test drive vehicle in both 2WD and 4WD modes to verify differential functions correctly
• Listen for abnormal noises from differential during operation
• After test drive, re-check differential fluid level and inspect for leaks
• Verify no vibrations are present that would indicate driveshaft misalignment
• Re-torque all mounting bolts after 50-100 miles of operation

Related trouble codes on this vehicle

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