Rear Differential

Complete removal and installation of the rear differential assembly, including disconnection of driveshaft, axle halfshafts, and all mounting hardware.

Warnings

Tools required

Parts

• Rear differential gasket or RTV sealant × 1 — Use OEM specification
• Differential mounting bushings (if worn) × 2 — Use OEM specification
• Axle seals (if replacing) × 2 — Use OEM specification
• Cotter pins for axle nuts × 2 — Use OEM specification
• Shop rags × 10 — Generic

Fluids

• 75W-90 GL-5 gear oil with limited-slip additive — 3.5 qt

Preparation

1. Park vehicle on level ground 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 designated frame lift points.
5. Remove both rear wheels completely.
6. Allow differential to cool completely if vehicle has been driven recently.

Procedure

1. 1

   Drain differential fluid
   Place drain pan under differential. Remove the differential cover bolts and carefully pry the cover off using a pry bar at the designated pry points. Allow all gear oil to drain completely into the pan. Inspect the drained fluid for metal particles or contamination that might indicate internal damage. Remove and discard the old gasket material from both the cover and differential housing using a scraper or wire brush.
2. 2

   Remove rear axle nuts
   Remove the axle nut retention (cotter pin or stake, as equipped) from both rear axle nuts. With the vehicle's brakes applied to prevent hub rotation, use a breaker bar and socket to remove both rear axle nuts. These nuts are torqued to a high value and will require significant force; verify the exact axle nut torque specification against the factory service manual before reassembly. Set the nuts aside and discard any old retention hardware.
3. 3

   Disconnect rear halfshafts from differential
   Locate the fasteners connecting each halfshaft inner joint to the differential output flanges. Confirm the exact bolt count per side against the 1992 Viper service manual, then remove all fasteners and carefully separate the halfshafts from the differential. Support the outer ends of the halfshafts with wire or bungee cords to prevent them from hanging and damaging the CV boots. Do not allow the halfshafts to hang freely by their own weight.
4. 4

   Mark and disconnect driveshaft
   Use a paint marker or scribe to mark the alignment between the driveshaft flange and the differential pinion flange. This ensures correct phasing during reinstallation. Remove the driveshaft bolts connecting the driveshaft to the differential pinion flange (verify exact bolt count against the 1992 Viper service manual). Support the driveshaft and carefully lower it away from the differential. Secure the driveshaft to the exhaust or undercarriage with wire to prevent it from hanging.
5. 5

   Disconnect differential mounting points
   Position a transmission jack or differential jack under the center of the differential housing. Raise the jack slightly to take the weight off the mounting bolts. Locate the differential mounting bolts at the front and rear mounting points. Locate the differential mounting bolts at the front and rear mounting points (verify exact bolt count and configuration for the 1992 Viper against the factory service manual). Remove all mounting bolts while supporting the differential with the jack.
6. 6

   Remove differential assembly
   With all mounting hardware disconnected, carefully lower the differential assembly on the transmission jack. Guide it down and out from under the vehicle, being mindful of brake lines, ABS sensors, and other components. The differential will tilt as it lowers due to its shape. Once clear of the vehicle, roll the jack away to a suitable work area. The unit weighs approximately 150 lbs, so handle with appropriate care.
   ⚠Control the descent carefully. The differential is heavy and awkwardly shaped. Have an assistant guide it if possible.
7. 7

   Inspect differential mounts and bushings
   With the differential removed, inspect all mounting bushings for cracks, tears, or excessive wear. Check the mounting brackets on both the differential and subframe for damage or elongated bolt holes. Inspect the CV joint flanges on the differential for wear or damage. Check the pinion flange for play or wear. Replace any worn components before reinstallation.
8. 8

   Position and install differential assembly
   Position the differential assembly on the transmission jack and raise it into position under the vehicle. Align the mounting points with the subframe brackets. Install all 4 mounting bolts finger-tight initially. Once all bolts are started, torque them to specification using a torque wrench. Ensure the differential is properly seated in the mounts before final torquing.
9. 9

   Reconnect driveshaft
   Align the driveshaft flange with the differential pinion flange using the alignment marks made during disassembly. Install all driveshaft bolts (verify exact count in the service manual) and torque them to specification in a crisscross pattern. Verify the driveshaft rotates freely without binding after installation.
10. 10

    Reconnect rear halfshafts
    Remove the support wires from the halfshafts. Align each halfshaft CV joint with its corresponding differential output flange. Install all inner joint bolts per side (verify exact count in the service manual) and torque them to specification in a star pattern. Ensure the CV joints are fully seated against the flanges before torquing.
11. 11

    Install rear axle nuts
    Install both rear axle nuts onto the halfshaft ends. With the vehicle's brakes applied to prevent hub rotation, torque each axle nut to the factory-specified value (verify in the 1992 Viper service manual). Secure each nut using the correct OEM retention method (new cotter pin or fresh stake, as equipped). Verify the retention is properly seated and cannot back out.
    ℹ️Always use new cotter pins. Never reuse old cotter pins as they may be weakened.
12. 12

    Install differential cover and refill
    Clean all gasket surfaces thoroughly. Install a new differential cover gasket or apply a bead of RTV sealant per manufacturer specification. Install the differential cover and torque all bolts to specification in a crisscross pattern. Wait for RTV to cure if used (typically 15-30 minutes) before filling. Remove the differential fill plug (located on the front or side of the housing). Using a fluid pump or funnel with hose, fill the differential with 75W-90 GL-5 gear oil with limited-slip additive until fluid reaches the bottom of the fill hole (verify the exact fill capacity against the 1992 Viper service manual). Reinstall the fill plug.
13. 13

    Install wheels and lower vehicle
    Install both rear wheels. Thread all lug nuts by hand to prevent cross-threading. Torque the lug nuts to specification in a star pattern. Lower the vehicle to the ground and perform a final torque check on all lug nuts with the vehicle weight on the wheels.

Reassembly

1. Reassembly is covered in the removal steps above, performed in reverse order.
2. Always use new cotter pins for axle nuts.
3. Verify all fasteners are torqued to specification using a calibrated torque wrench.
4. Check for any fluid leaks from the differential cover after the first 50 miles of driving.

Verification

• Start the engine and verify no unusual noises from the differential.
• With the vehicle on jack stands and in neutral, rotate the rear wheels by hand to verify smooth operation and no binding.
• Check for any fluid leaks around the differential cover, axle seals, and pinion seal.
• Test drive the vehicle at low speed and verify smooth operation through turns and acceleration.
• After the first 50-100 miles, recheck the differential fluid level and inspect for leaks.
• Verify no vibration or unusual noises during normal driving conditions.

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