Differential Cover Gasket

Remove and replace the rear differential cover gasket on a 2008 Dodge Viper, including draining and refilling the differential with fresh synthetic gear oil.

Warnings

Tools required

Parts

• Differential cover gasket × 1 — Use OEM specification or Fel-Pro RDS55496
• Differential cover bolt set (if reusing bolts show wear) × 1 — Use OEM specification

Fluids

• 75W-90 synthetic gear oil — 2.75 qt

Preparation

1. Park vehicle on level ground and engage parking brake
2. Place wheel chocks in front of front wheels
3. If vehicle was recently driven, allow differential to cool for at least 1 hour
4. Raise rear of vehicle using lift or jack stands at manufacturer-specified lift points
5. Verify vehicle is secure and stable before working underneath
6. Position drain pan underneath rear differential cover

Procedure

1. 1

   Access the differential cover
   Locate the rear differential cover at the rear of the differential housing. The cover is a cast aluminum component secured to the differential housing by its bolts (verify exact bolt count against 2008 Dodge Viper service documentation before ordering the bolt set). Inspect the area and note any exhaust components that may limit access, though on the Viper the differential is typically accessible without exhaust removal.
2. 2

   Begin draining gear oil
   Position the drain pan directly beneath the differential cover. Using a 3/8" or 1/2" drive ratchet with appropriate socket, begin loosening the differential cover bolts in a cross-pattern, starting from the top. Loosen each bolt 2-3 turns but do not fully remove yet. As bolts loosen, gear oil will begin seeping from the cover gasket.
3. 3

   Remove upper cover bolts
   Once oil begins draining, remove the upper 10 differential cover bolts completely, working from top to bottom. Leave the two lowest bolts partially threaded to support the cover weight. Allow gear oil to drain for several minutes until flow reduces to a slow drip.
4. 4

   Remove differential cover
   Remove the final two lower bolts while supporting the differential cover with your hand. Carefully pull the cover away from the housing, tilting the bottom edge down to allow remaining gear oil to drain into the pan. Set the cover aside on a clean surface. Expect used gear oil to drain into the pan; confirm the exact differential fluid capacity against 2008 Dodge Viper service documentation.
5. 5

   Clean differential housing mating surface
   Using a plastic or brass gasket scraper, carefully remove all old gasket material from the differential housing mating surface. Work carefully to avoid gouging the aluminum housing. Use a wire brush for stubborn material, then clean the surface thoroughly with brake cleaner and shop rags. The mating surface must be completely clean, dry, and free of oil residue for proper gasket sealing.
6. 6

   Clean differential cover
   Clean the differential cover mating surface using the same method as the housing. Remove all old gasket material with a scraper, then clean with brake cleaner. Inspect the cover for warping or damage. If the cover is bent or cracked, it must be replaced. Clean the exterior of the cover to remove accumulated road grime and oil residue.
7. 7

   Inspect differential internals
   With the cover removed, visually inspect the ring gear and pinion gear teeth for unusual wear, pitting, or damage. Check for metal debris in the bottom of the housing, which would indicate gear wear. If significant debris or gear damage is present, further differential service is required beyond gasket replacement. For normal maintenance, wipe out any minor residue with a clean shop rag.
8. 8

   Install new gasket
   Position the new differential cover gasket onto the cover (not the housing). Some gaskets are self-adhesive; others may require a thin bead of RTV silicone on the cover side only. Ensure the gasket aligns with all bolt holes and sits flat against the cover surface. If using RTV, allow it to tack up for 5 minutes before installation.
9. 9

   Install differential cover
   Carefully position the differential cover with new gasket onto the housing, aligning all 10 bolt holes. Start all 10 bolts by hand to ensure proper thread engagement and gasket alignment. Do not force any bolts; if resistance is met, verify gasket positioning and bolt hole alignment.
10. 10

    Torque differential cover bolts
    Using a torque wrench, tighten the 10 differential cover bolts in a cross-pattern (star pattern) to achieve even gasket compression. Tighten in three progressive passes in a cross/star pattern, with the final pass to the OEM-specified torque for the 2008 Dodge Viper rear differential cover bolts (verify the exact value against Dodge service documentation). This gradual tightening prevents gasket distortion and ensures even sealing.
11. 11

    Fill differential with gear oil
    Locate the differential fill plug on the side of the differential housing. Confirm the exact fill plug location and orientation against 2008 Dodge Viper service documentation before proceeding. Remove the fill plug using the appropriate socket. Using a fluid pump or funnel with extension tube, add gear oil of the OEM-specified grade and quantity through the fill hole (verify capacity, grade, and any required limited-slip friction modifier against 2008 Dodge Viper service documentation). Fill until oil begins to seep from the fill hole, indicating proper level. Fill until oil begins to seep from the fill hole, indicating proper level.
12. 12

    Install fill plug and check for leaks
    Clean the fill plug threads and reinstall the plug, tightening to specification. Wipe down the entire differential cover and housing with a clean rag. Start the vehicle and allow it to run for 1-2 minutes, then shut off. Inspect the differential cover gasket area carefully for any signs of oil seepage. If leaks are present, re-torque cover bolts or investigate gasket installation.

Reassembly

1. Lower vehicle from lift or jack stands
2. Remove wheel chocks
3. Dispose of used gear oil properly at a recycling facility
4. Test drive vehicle and monitor for any unusual rear differential noise or vibration

Verification

• Verify no gear oil leaks are present around differential cover after test drive
• Check differential fill plug is tight and secure
• Confirm proper differential operation with no abnormal noise during acceleration and deceleration
• Re-inspect cover gasket area after 50-100 miles of driving for any delayed seepage

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