Replace the rear axle seal(s) on a 2014 Ram 2500 4WD with 6.7L Cummins Diesel, requiring differential cover removal, axle shaft extraction, and seal replacement.

Warnings

Tools required

Parts

• Rear axle shaft seal(s) × 2 — Use OEM Mopar specification for AAM 11.5 inch rear axle
• Differential cover gasket × 1 — Use OEM specification or RTV silicone
• Cotter pin(s) for axle nut × 2 — Use appropriate size per axle shaft specification

Fluids

• Mopar 75W-140 Synthetic Gear Lubricant — 2 qt

Preparation

1. Park vehicle on level surface and engage parking brake
2. Chock front wheels securely
3. Loosen rear wheel lug nuts while vehicle is on ground
4. Raise rear of vehicle and support securely on jack stands at frame rails
5. Remove rear wheels completely
6. Place drain pan under differential cover

Procedure

1. 1

   Drain differential fluid
   Remove the differential cover bolts in a crisscross pattern, starting from the top. Leave two top bolts loosely installed until fluid begins draining. Once fluid flow slows, remove remaining bolts and carefully remove cover. Allow all fluid to drain completely into drain pan.
   Torque spec

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

   Clean differential cover and housing
   Use gasket scraper to remove all old gasket material from both the differential cover and housing mating surfaces. Clean surfaces thoroughly with brake parts cleaner and wipe dry. Inspect cover for warping or damage. Clean the inside of the differential housing opening with shop towels, being careful not to contaminate ring and pinion gears.
   ⚠Do not allow debris or old gasket material to fall into the differential housing. Cover opening with clean shop towel when not actively working.
3. 3

   Remove axle shaft retaining hardware
   Locate the axle shaft retaining nuts or lock rings at the outer end of each axle shaft (visible from brake assembly side). If equipped with cotter pins, remove and discard old cotter pins. Remove axle shaft retaining nuts using appropriate socket. On full-floating axles, there will be multiple bolts around the outer flange.
   Torque spec

   Axle Nut250 Nm (184 lb-ft)
4. 4

   Extract axle shafts
   Carefully pull axle shaft straight out from the axle tube. For full-floating axles, the shaft should slide out once retaining hardware is removed. If shaft is stuck, tap gently on the flange with rubber mallet while pulling. Repeat for both sides. Inspect axle shaft seal surface for wear, grooves, or damage that could compromise new seal.
   ⚠Support axle shaft weight during removal to prevent damage to shaft or brake components. Shafts can be heavy.
5. 5

   Remove old axle seals
   Using seal puller or slide hammer with hook attachment, carefully extract old axle seals from each axle tube. Hook the tool into the seal lip or body and pull straight out. Avoid damaging the axle tube bore during removal. Inspect axle tube bore for scoring, corrosion, or damage that could prevent proper seal seating.
   ⚠Do not use screwdrivers or pry bars to remove seals as this can damage the axle tube bore and cause new seal leaks.
6. 6

   Prepare and install new axle seals
   Clean axle tube bore thoroughly with brake parts cleaner and wipe dry. Lightly coat the outer diameter of new seal with gear oil. Lightly coat seal lip with gear oil as well. Position new seal squarely at the axle tube opening with seal lip facing inward (toward differential). Using appropriately sized seal driver or large socket that contacts only the outer seal edge, drive seal into bore until it seats fully and is flush or slightly recessed per manufacturer specification. Repeat for both sides.
   ⚠Ensure seal is driven in straight and square. Cocking the seal during installation will cause leaks and premature seal failure.
7. 7

   Reinstall axle shafts
   Lightly coat axle shaft seal surface with gear oil. Carefully align axle shaft splines with differential side gear and slide shaft into axle tube. Push shaft in until it fully seats into the differential. Ensure shaft does not contact or damage new seal lip during installation. Repeat for both sides. Verify shafts are fully seated by checking engagement depth.
   ⚠Use care when inserting axle shaft through new seal to avoid cutting or rolling the seal lip, which would cause immediate leakage.
8. 8

   Install axle shaft retaining hardware
   Install axle shaft retaining nuts or reinstall flange bolts on full-floating axle. Torque axle nuts to specification. Install new cotter pins through axle nut castle nut slots and bend properly to secure, or stake nut per manufacturer specification if required. Verify axle shafts have minimal end play and rotate freely.
   Torque spec

   Axle Nut250 Nm (184 lb-ft)
9. 9

   Prepare and install differential cover
   Apply a continuous bead of RTV silicone gasket maker to the differential cover mating surface (or install new preformed gasket per preference). If using RTV, apply approximately 1/8 inch bead around all bolt holes and cover perimeter. Position cover on differential housing and install all bolts finger-tight. Torque differential cover bolts in a crisscross pattern to specification, working from center outward.
   ℹ️If using RTV silicone, allow appropriate cure time per product specifications before filling with fluid. Some products require 1 hour before filling and 24 hours before operation.
   Torque spec

   Differential Cover Bolts35 Nm (26 lb-ft)
10. 10

    Refill differential with gear oil
    Locate differential fill plug on front of differential housing. Remove fill plug. Using fluid pump or squeeze bottle, fill differential with Mopar 75W-140 Synthetic Gear Lubricant until fluid reaches bottom of fill hole (approximately 2 quarts total). Reinstall fill plug and torque to specification if torque spec is provided. Wipe away any spilled fluid.
    ℹ️Proper fill level is to bottom of fill plug hole. Overfilling can cause seal leakage and excessive pressure buildup.
11. 11

    Reinstall wheels and lower vehicle
    Reinstall rear wheels onto hubs. Install lug nuts and tighten in star pattern finger-tight. Lower vehicle until tires just contact ground but weight is still on jack stands. Torque wheel lug nuts to specification in star pattern. Fully lower vehicle and remove jack stands. Perform final lug nut torque verification in star pattern.
    Torque spec

    Wheel Lug Nuts140 Nm (103 lb-ft)

Reassembly

1. Double-check all fasteners are torqued to specification, especially axle nuts and differential cover bolts
2. Verify cotter pins are properly installed and secured on axle shaft nuts
3. Clean any spilled gear oil from axle housing, brake components, and frame
4. Dispose of used gear oil according to local environmental regulations

Verification

• Start engine and allow to idle, verify no leaks from differential cover or axle seals
• Test drive vehicle for 5-10 miles, including turns in both directions and moderate acceleration
• Re-inspect differential cover and both axle seals for any signs of leakage
• Check differential fluid level after test drive and top off if necessary
• Monitor for leaks over next 100 miles of operation
• Re-torque wheel lug nuts after 50-100 miles of driving

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