This procedure drains and replaces the rear differential fluid on a 2014 Ram 2500 with 6.7L Cummins diesel engine, ensuring proper lubrication of the rear axle components.

Warnings

Tools required

Parts

• Differential cover gasket × 1 — Mopar 68211918AA or equivalent
• RTV silicone gasket maker (if gasket not used) × 1 — Mopar Ultra Black or equivalent

Fluids

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

Preparation

1. Park vehicle on level surface and engage parking brake
2. Place wheel chocks in front of front wheels
3. If recently driven, allow differential to cool for at least 30 minutes
4. Raise rear of vehicle using floor jack at rear axle differential housing
5. Support vehicle with jack stands under frame rails behind rear axle
6. Ensure vehicle is stable and level before working underneath

Procedure

1. 1

   Position drain pan and remove cover bolts
   Position drain pan directly under differential cover. Using a 3/8" drive ratchet and appropriate socket, loosen all differential cover bolts in a crisscross pattern, leaving the top two bolts partially threaded. This allows the cover to break free gradually.
2. 2

   Remove cover and drain fluid
   Carefully pry the bottom of the differential cover away from the housing using a gasket scraper, allowing fluid to drain into the pan. Once fluid flow slows, remove the remaining top bolts and completely remove the cover. Be prepared for additional fluid to drain. Tilt cover to drain any remaining fluid from inside the cover.
   ⚠Fluid will drain quickly once cover begins to separate. Keep drain pan positioned to catch all fluid.
3. 3

   Clean cover and housing mating surfaces
   Use a gasket scraper to remove all old gasket material from both the differential cover and the axle housing mating surface. Follow with a wire brush to remove any remaining residue. Wipe both surfaces clean with shop rags and brake cleaner. Inspect for any damage, warping, or cracks. The mating surfaces must be completely clean and free of debris for proper sealing.
4. 4

   Inspect internal components
   With the cover removed, visually inspect the ring gear, pinion gear, and differential components for excessive wear, metal shavings, or damage. Check the bottom of the housing for metal debris. A small amount of fine metallic paste is normal, but chunks or excessive material indicates potential component failure. If excessive wear is found, further diagnosis is required before refilling.
5. 5

   Install new gasket on cover
   If using a pre-formed gasket, position it on the differential cover and ensure all bolt holes align properly. If using RTV silicone, apply a continuous 1/8-inch bead around the inside of the bolt holes on the cover, ensuring the bead surrounds all bolt holes. Do not allow RTV to extend into the interior where it could contaminate the fluid.
6. 6

   Install differential cover
   Carefully position the cover with gasket onto the axle housing, ensuring proper alignment. Start all differential cover bolts by hand to avoid cross-threading. Once all bolts are started, tighten them in a crisscross pattern gradually to avoid distorting the cover. Use a torque wrench to tighten all bolts to specification in three progressive passes (1/3 torque, 2/3 torque, then final torque).
   ℹ️If using RTV silicone without a gasket, allow 15-20 minutes for initial setup before torquing bolts, then wait 1 hour before filling with fluid.
   Torque spec

   Differential Cover Bolts35 Nm (26 lb-ft)
7. 7

   Fill differential with gear oil
   Locate the fill plug on the front side of the differential housing (passenger side, approximately mid-height). Remove the fill plug using appropriate socket. Using a fluid pump or squeeze bottle, add Mopar 75W-140 Synthetic Gear Lubricant through the fill hole. Fill until fluid begins to drip from the fill hole, indicating proper level (approximately 2 quarts total). Reinstall and hand-tighten the fill plug.
8. 8

   Lower vehicle and verify fluid level
   Remove jack stands and carefully lower vehicle to the ground, ensuring it is on level surface. With vehicle level, recheck the fill plug. Fluid should be at the bottom edge of the fill hole. Add additional fluid if necessary. Once level is confirmed correct, torque the fill plug to specification.
   ⚠Differential must be filled and checked with vehicle on level ground for accurate fluid level.

Reassembly

1. Ensure all bolts are torqued to specification before driving vehicle
2. If RTV silicone was used, allow full cure time (24 hours) before extended highway driving
3. Dispose of used gear oil properly at a recycling center or auto parts store

Verification

• Start engine and allow to idle, then shift through all gears while stationary
• Test drive vehicle for 5-10 minutes, making several turns in both directions
• After test drive, recheck differential cover for any signs of leakage around gasket
• Verify no drips or seepage from fill plug
• Listen for any abnormal whining, grinding, or howling noises from rear axle during acceleration and deceleration
• After 50-100 miles of driving, recheck fluid level and inspect for leaks

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