Rear Differential

Complete removal and replacement of the rear differential assembly on a 4WD Dodge Ram 2500 with 5.9L Cummins diesel engine, including driveshaft removal, axle shaft disconnection, and differential housing R&R.

Warnings

Tools required

Parts

• Rear differential cover gasket or RTV silicone × 1 — Use OEM specification or quality aftermarket
• Differential fluid × 4 — 75W-90 synthetic gear oil
• Cotter pins for axle nuts × 2 — Use OEM specification
• Shop towels and cleaning solvent × 1 — Brake cleaner or degreaser

Fluids

• 75W-90 synthetic gear oil — 3.5 qt

Preparation

1. Park vehicle on level, solid surface and engage parking brake
2. Chock front wheels securely
3. Raise rear of vehicle and support on jack stands under frame rails behind rear axle
4. Remove both rear wheels
5. Verify differential is cool to touch before proceeding

Procedure

1. 1

   Drain differential fluid
   Position drain pan under rear differential cover. Remove all differential cover bolts in crisscross pattern, leaving top two bolts loosely installed. Carefully pry cover away at bottom to allow fluid to drain. Once drained, remove remaining bolts and cover. Remove and discard old gasket material. Clean cover and housing mating surfaces thoroughly with wire brush and solvent.
   Torque spec

   Differential Cover Bolts35 Nm (26 lb-ft)
2. 2

   Mark and disconnect rear driveshaft
   Mark the rear driveshaft flange position relative to the differential pinion yoke with paint or punch marks to ensure correct phasing during reinstallation. Support driveshaft with wire or strap. Remove the four driveshaft bolts or U-joint strap bolts at the differential yoke. Carefully slide driveshaft rearward to separate from pinion yoke. Support driveshaft and lower it clear of work area. Do not allow driveshaft to hang unsupported by transmission output shaft.
   ℹ️Keep U-joint caps in place with tape if straps are removed to prevent needle bearing loss.
   Torque spec

   Driveshaft Bolts75 Nm (55 lb-ft)

   Driveshaft U-Joint Straps20 Nm (15 lb-ft)
3. 3

   Remove axle shaft cotter pins and nuts
   Remove the axle shaft flange bolts from the hub on both sides. The rear axle on this truck is a full-floating design; the axle shafts are retained by a bolted flange, not by a castellated nut and cotter pin. Withdraw each axle shaft from the housing and set aside on a clean surface. Mark left and right sides if reusing parts. Axle shaft flange bolts are moderately torqued; refer to the service manual specification when reinstalling.
   ⚠Axle nuts are torqued to 250 Nm and will require substantial force to break loose.
4. 4

   Disconnect CV joint bolts at differential
   On this solid rear axle, the differential is integral to the axle housing and there are no CV joints or side flanges to disconnect. If the full carrier/axle assembly is being removed, the axle shafts are withdrawn from the housing after unbolting the shaft flanges; otherwise this step is not applicable.
   ⚠Support axle shafts to prevent excessive CV joint angle which can damage boots or joints.
   Torque spec

   CV Joint Bolts61 Nm (45 lb-ft)
5. 5

   Disconnect brake line and ABS sensor
   Disconnect brake line at junction on differential housing if equipped. Have rag ready to catch minimal brake fluid spillage. Disconnect ABS sensor wiring harness if equipped with rear ABS sensors. Secure brake line and wiring out of way to prevent damage during differential removal.
   ℹ️Cap or plug brake line fittings to minimize fluid loss and prevent contamination.
6. 6

   Support differential with transmission jack
   Position transmission jack or heavy-duty floor jack under center of differential housing. Raise jack until it just contacts and supports the differential weight. Secure differential to jack with chain or strap to prevent it from shifting during removal. Verify jack is centered and stable.
   ⚠️Differential must be securely supported before removing mounting hardware. Assembly weighs approximately 200 pounds.
7. 7

   Remove shock absorber lower mounting bolts
   Remove lower mounting bolts for both rear shock absorbers where they attach to axle mounting brackets. Allow shocks to hang freely. This provides clearance for differential removal.
8. 8

   Remove track bar and sway bar links
   If equipped, disconnect track bar from axle bracket. Remove sway bar end links from axle mounting points. Set hardware aside and label for reinstallation.
9. 9

   Remove differential mounting hardware
   Remove all U-bolts or mounting bolts that secure differential housing to leaf spring perches. There are typically four U-bolts (two per side). Remove U-bolt nuts and backing plates. Keep all hardware organized by location for reinstallation.
   ⚠As final mounting hardware is removed, ensure transmission jack is securely supporting differential weight.
10. 10

    Remove differential assembly
    With assistant helping to stabilize, carefully lower differential assembly on transmission jack. Guide it away from leaf springs and out from under vehicle. Move slowly and check for any remaining connections. Once clear, lower jack completely and remove differential from jack.
    ⚠️Use extreme caution when lowering heavy differential assembly. Ensure path is clear and assistant is helping to guide.
11. 11

    Install replacement or rebuilt differential
    Mount replacement differential securely on transmission jack with chain or strap. Raise jack and carefully guide differential into position between leaf springs, aligning spring perches with differential mounting pads. An assistant should guide from outside while operator controls jack. Align U-bolt holes once differential is positioned correctly.
    ℹ️Ensure pinion yoke is oriented correctly to align with driveshaft before fully securing differential.
12. 12

    Install differential mounting hardware
    Install U-bolts and backing plates over spring perches. Thread nuts onto U-bolts and tighten gradually in crisscross pattern to pull differential down evenly onto spring perches. Torque U-bolt nuts to specification. Do not fully remove jack support until all mounting hardware is installed and torqued.
13. 13

    Reconnect suspension components
    Reinstall shock absorber lower mounting bolts and torque to specification. Reconnect track bar and sway bar links if equipped. Torque all fasteners to specification.
14. 14

    Reconnect CV axle shafts
    Clean CV joint and differential flange mating surfaces. Align CV joints with differential side flanges. Install CV joint bolts and torque evenly in star pattern to specification. Repeat for both left and right sides.
    Torque spec

    CV Joint Bolts61 Nm (45 lb-ft)
15. 15

    Install axle nuts and secure
    Reinstall the axle shafts and torque the shaft flange bolts to the service manual specification. Verify fasteners are properly secured.
    ⚠Always use new cotter pins. Never reuse old cotter pins on critical fasteners.
16. 16

    Reconnect rear driveshaft
    Align driveshaft with pinion yoke using reference marks made during disassembly. Install driveshaft bolts or U-joint strap bolts and torque evenly to specification. Verify driveshaft phasing is correct and matches original orientation.
    ⚠Incorrect driveshaft phasing will cause severe vibration. Always align reference marks.
    Torque spec

    Driveshaft Bolts75 Nm (55 lb-ft)

    Driveshaft U-Joint Straps20 Nm (15 lb-ft)
17. 17

    Reconnect brake line and ABS sensor
    Reconnect brake line at differential housing junction. Tighten fitting securely. Reconnect ABS sensor wiring harness if equipped. Verify connections are secure and wiring is routed away from rotating components.
18. 18

    Install differential cover and fill
    Install new gasket or apply continuous 1/8-inch bead of RTV silicone to differential cover mating surface. Install cover and bolts, tightening in crisscross pattern to specification. Allow RTV to cure per manufacturer instructions if used. Remove fill plug and fill differential with 75W-90 gear oil until oil reaches the bottom of the fill hole (typically about 3.5 quarts, but fill to the hole rather than by volume). If the axle is equipped with a limited-slip differential, add the specified quantity of friction modifier. Reinstall fill plug.
    ℹ️If using RTV, allow 30 minutes cure time before filling with oil. Wait 24 hours before driving for full cure.
    Torque spec

    Differential Cover Bolts35 Nm (26 lb-ft)
19. 19

    Reinstall wheels and lower vehicle
    Install rear wheels and hand-tighten lug nuts in star pattern. Lower vehicle until wheels just contact ground. Torque lug nuts to specification in star pattern. Fully lower vehicle and remove jack stands.
    Torque spec

    Wheel Lug Nuts183 Nm (135 lb-ft)

Reassembly

1. Bleed brake system if brake lines were opened during procedure
2. Check for any fluid leaks at differential cover, brake lines, and axle seals
3. Verify all fasteners are torqued to specification
4. Remove wheel chocks

Verification

• Start engine and verify no unusual noises from rear differential
• Test drive vehicle at various speeds and verify smooth operation with no vibration or noise
• Check for gear oil leaks at differential cover after test drive
• Verify proper brake operation if brake lines were disconnected
• Recheck differential fluid level after test drive and top off if necessary

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