Ring and Pinion

Replace the ring and pinion gears in the rear differential of a 2005 Dodge Viper, including disassembly of the carrier assembly, gear installation, backlash and preload adjustment, and reassembly with proper gear marking compound verification.

Warnings

Tools required

Parts

• Ring and pinion gear set (OEM or aftermarket with carrier shims) × 1 — Specify ratio (e.g., 3.07, 3.55, 3.73)
• Pinion bearing set (inner and outer) × 1 — Use OEM specification
• Carrier bearing set × 1 — Use OEM specification
• Pinion seal × 1 — Use OEM specification
• Pinion nut × 1 — Use OEM specification
• Crush sleeve or solid pinion spacer × 1 — Depends on setup; use OEM specification
• Differential cover gasket or RTV sealant × 1 — Use OEM specification or Mopar RTV
• Ring gear bolts × 1 — Use OEM specification with thread locker
• Pinion shim set × 1 — Included with gear set or purchase separately
• Carrier shim set × 1 — Included with gear set or purchase separately

Fluids

• 75W-140 synthetic GL-5 rear differential fluid — 3 qt

Preparation

1. Park vehicle on level ground and engage parking brake
2. Chock front wheels securely
3. Raise rear of vehicle and support on jack stands at the frame rails behind the rear axle
4. Remove both rear wheels
5. Place drain pan under differential
6. Allow differential to cool if vehicle was recently driven

Procedure

1. 1

   Mark and Remove Driveshaft
   Use white paint or a marker to mark the relationship between the driveshaft flange and the pinion flange for proper reinstallation alignment. Remove the 4 U-joint strap bolts at the rear differential. Support the driveshaft and carefully slide it rearward to separate it from the pinion flange. Lower the driveshaft and support it out of the way or remove completely.
   Torque spec

   Driveshaft U-Joint Straps20 Nm (15 lb-ft)
2. 2

   Drain Differential Fluid
   Position drain pan under the differential cover. Remove all differential cover bolts in a crisscross pattern. Carefully pry the cover away from the housing using a pry bar at the designated pry points. Allow all fluid to drain completely into the pan. Remove the cover and gasket material.
   Torque spec

   Differential Cover Bolts35 Nm (26 lb-ft)
3. 3

   Remove Axle Shafts
   The Viper uses an independent rear suspension with half-shafts bolted to the differential output flanges rather than C-clip retained axle shafts. Disconnect the inner CV/half-shaft flange bolts from the differential stub flanges and support the half-shafts aside. Inspect the flanges, stub shafts, and output seals for wear.
   ⚠Support axle shafts during removal to prevent damage to shaft splines or housing seals.
4. 4

   Mark and Remove Carrier Bearing Caps
   Use a center punch or paint marker to mark the carrier bearing caps and housing for proper orientation during reassembly. The caps are matched to their respective sides and must be reinstalled in the same position. Remove the carrier bearing cap bolts. Carefully remove both bearing caps and set them aside with their bolts.
   ℹ️Carrier bearing caps are not interchangeable and must be returned to their original positions.
5. 5

   Remove Carrier Assembly
   Install a case spreader tool on the differential housing per the tool manufacturer's instructions. Spread the housing just enough to allow carrier removal (typically 0.010-0.015 inches maximum spread). Use pry bars to carefully pry the carrier assembly with ring gear attached out of the housing. Remove the case spreader immediately after carrier removal to prevent housing distortion. Set the carrier assembly aside and remove the carrier bearing shims, keeping track of their thickness and side for reference.
   ⚠️Do not over-spread the differential housing. Excessive spreading can permanently deform the housing. Follow case spreader manufacturer limits.
6. 6

   Remove Pinion Nut and Flange
   Use a pinion holding tool or have an assistant apply the service brake while using an impact wrench to remove the pinion nut. Mark the position of the pinion flange relative to the pinion shaft with paint. Count and record the number of threads visible above the pinion nut for reference during reassembly. Use a flange puller to remove the pinion flange from the pinion shaft. Remove the pinion seal if replacing.
   ℹ️The pinion nut should not be reused. Always install a new pinion nut during reassembly.
7. 7

   Remove Pinion and Bearings
   Carefully drive the pinion shaft out of the housing from the front using a brass drift or soft mallet. Catch the pinion as it exits to prevent it from falling. Remove the rear pinion bearing from the housing using a bearing puller or press. Remove the front pinion bearing, crush sleeve (if equipped), pinion depth shim, and rear bearing from the pinion shaft. Keep all components organized and note the original shim thickness.
   ⚠The crush sleeve (if equipped) must be replaced during reassembly. It cannot be reused once collapsed.
8. 8

   Remove Ring Gear from Carrier
   Mark the orientation of the ring gear to the carrier with paint or punch marks. Remove all ring gear bolts using a crisscross pattern. Tap the ring gear with a dead blow hammer to break it loose from the carrier. Remove the ring gear and clean all mating surfaces on the carrier thoroughly.
   ℹ️Ring gear bolts are high-strength fasteners and should be replaced with new bolts supplied with the ring and pinion set.
9. 9

   Clean and Inspect Components
   Thoroughly clean the differential housing, carrier, and all bearing bores with solvent and shop towels. Inspect the housing for cracks, scoring, or damage. Inspect carrier bearing bores and surfaces for wear or damage. Check axle housing bearing surfaces for pitting or scoring. Replace any damaged components before proceeding.
   ℹ️Any debris left in the housing or on components can cause premature gear failure. Ensure all surfaces are completely clean.
10. 10

    Install Rear Pinion Bearing Race
    Install the new rear pinion bearing outer race into the housing using a bearing race driver or press. Ensure the race is fully seated and square in the bore. Verify proper seating by checking that the race is flush with the housing bore.
    ⚠Bearing races must be driven in squarely to prevent cocking or damage. Use proper bearing installation tools.
11. 11

    Calculate and Install Pinion Depth Shim
    Use a pinion depth gauge to determine the correct pinion depth shim thickness. The new ring and pinion set will have markings indicating the required adjustment from nominal. Install the calculated shim on the pinion shaft. Press the new rear pinion bearing onto the pinion shaft using a bearing installer or press, ensuring it seats against the shim.
    ⚠Pinion depth is critical to proper gear contact pattern. Incorrect depth will cause noise and premature wear. Follow the gauge instructions precisely and verify calculations.
12. 12

    Install Front Pinion Bearing Race and Pinion Assembly
    Install the front pinion bearing outer race into the housing using a bearing race driver. Install the new crush sleeve or solid spacer (per your setup) onto the pinion shaft. Install the front pinion bearing onto the pinion shaft. Apply a light coat of gear oil to the pinion seal lip and install the new pinion seal into the housing. Carefully insert the pinion assembly into the housing from the rear, guiding it through the front bearing and seal.
    ℹ️Do not damage the pinion seal during installation. Use a seal driver if available to ensure proper seating.
13. 13

    Install Pinion Flange and Set Preload
    Install the pinion flange onto the pinion shaft, aligning it with the marks made during disassembly. Install the new pinion nut and tighten in stages using a holding tool. Tighten the nut while checking pinion bearing preload with an inch-pound torque wrench on the pinion nut. For new bearings, rotating torque should be 20-30 inch-pounds for the Viper Dana rear axle. Continue tightening the pinion nut in small increments until the proper preload is achieved. Do not back off the nut if you exceed preload; the crush sleeve cannot be reused if loosened.
    ⚠️Do not loosen the pinion nut to reduce preload. If preload is exceeded, the crush sleeve (if equipped) is collapsed and must be replaced. You must start over with a new crush sleeve.
    ⚠Measure rotating torque, not breakaway torque. Rotate the pinion several revolutions before taking the measurement.
14. 14

    Install Ring Gear on Carrier
    Clean the ring gear and carrier mating surfaces thoroughly. Position the new ring gear on the carrier, aligning the bolt holes and orientation marks. Install the new ring gear bolts with thread locker as specified by the gear set manufacturer. Tighten the bolts in a crisscross pattern in multiple stages to the manufacturer's specification (typically 70-75 ft-lb for Viper applications, but verify with gear set instructions).
    ℹ️Use only the ring gear bolts supplied with the new gear set. These are grade-specific fasteners.
15. 15

    Install Carrier Bearings
    Press or drive the new carrier bearings onto the carrier assembly using a bearing installer that contacts only the inner race. Ensure the bearings are fully seated against the carrier shoulders. Install carrier bearing shims on both sides of the carrier. Start with shims approximately the same thickness as the original shims removed, understanding that adjustment will be required.
    ⚠Carrier bearings must be installed with the correct orientation and fully seated. Improper installation will cause bearing failure.
16. 16

    Install Carrier Assembly and Set Backlash
    Apply gear oil to the carrier bearings. Install the case spreader on the housing and spread it just enough to allow carrier installation. Carefully install the carrier assembly with ring gear into the housing. Remove the case spreader immediately. Install the carrier bearing caps in their original positions per the marks made during disassembly. Install cap bolts and tighten finger-tight initially. Mount a dial indicator on the housing with the plunger contacting a ring gear tooth at 90 degrees to the tooth face. Check backlash by holding the pinion stationary and rocking the ring gear back and forth. Backlash should be 0.005-0.009 inches for the Viper rear differential. Adjust backlash by moving shims from one side of the carrier to the other (adding to one side while removing the same thickness from the other maintains bearing preload while changing backlash). Adding shim thickness to the ring gear side decreases backlash; adding to the opposite side increases backlash.
    ⚠Backlash must be checked at 3-4 positions around the ring gear to ensure proper carrier bearing adjustment and no runout issues.
17. 17

    Set Carrier Bearing Preload
    Once backlash is within specification, add 0.002-0.004 inches of shim thickness to EACH side of the carrier to establish carrier bearing preload. This increases the total shim pack while maintaining backlash. Verify backlash remains within specification after adding preload shims. Torque the carrier bearing cap bolts to specification in a crisscross pattern.
    ℹ️Proper carrier bearing preload is critical for gear life. Insufficient preload allows the carrier to move, causing gear noise and wear.
18. 18

    Check Gear Contact Pattern
    Apply gear marking compound (Prussian blue) to several teeth on the ring gear, coating both the drive and coast sides. Rotate the pinion through several revolutions in both directions under light load (apply resistance to the ring gear with a pry bar or soft wood block). Remove the carrier and examine the contact pattern on the ring gear teeth. The pattern should be centered on the tooth face with approximately equal contact on drive and coast sides. If the pattern is too close to the toe (inner edge), add pinion depth shim; too close to the heel (outer edge), remove pinion depth shim. If the pattern is too high on the tooth (top land), move the ring gear closer to the pinion by adding shim to the ring gear side; too low (root), move away by adding shim to the opposite side. Repeat adjustments and pattern checks until the pattern is correct.
    ⚠Adjusting pinion depth requires disassembling the pinion, which means replacing the crush sleeve and resetting pinion preload. Make small adjustments (0.002-0.003 inches) at a time.
    ℹ️A perfect contact pattern is ideal but not always achievable. The pattern should be centered and avoid the toe edge and top land, which are high-stress areas.
19. 19

    Final Assembly and Seal Differential Cover
    Once gear contact pattern and backlash are verified correct, clean all gear marking compound from the gears with solvent. Reconnect the half-shaft inner flanges to the differential output stub flanges, aligning any match marks. Install the flange bolts and tighten evenly to specification. Clean the differential cover and housing mating surfaces thoroughly. Install a new gasket or apply a 1/8-inch bead of RTV sealant to the cover. Install the differential cover and bolts. Tighten the cover bolts in a crisscross pattern to specification.
    Torque spec

    Differential Cover Bolts35 Nm (26 lb-ft)
20. 20

    Fill Differential and Install Driveshaft
    Fill the differential with 75W-140 synthetic GL-5 rear differential fluid through the fill hole until fluid reaches the bottom of the fill hole. Install the fill plug. Clean the pinion flange and driveshaft flange surfaces. Position the driveshaft to the pinion flange, aligning the marks made during disassembly. Install the U-joint strap bolts and tighten evenly to specification. Install the rear wheels and torque lug nuts to specification in a star pattern.
    Torque spec

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

    Wheel Lug Nuts142.4 Nm (105 lb-ft)
21. 21

    Break-In and Final Inspection
    Lower the vehicle from jack stands. Start the engine and allow it to idle while checking for leaks around the differential cover and pinion seal. Test drive the vehicle at moderate speeds for the first 15-20 miles, avoiding hard acceleration or high speeds. Vary the speed and load to allow the gears to wear in properly. After the initial break-in period, recheck the differential fluid level and inspect for leaks. Change the differential fluid after 500 miles to remove break-in debris.
    ⚠New gears require a break-in period. Avoid heavy loads, sustained high speeds, or aggressive driving for the first 500 miles. Failure to properly break in gears will cause premature wear.

Reassembly

1. Reassembly follows the reverse order of disassembly with critical attention to torque specifications and adjustment procedures
2. Carrier bearing caps must be installed in their original positions per orientation marks
3. Driveshaft must be aligned with marks made during removal to maintain driveline balance
4. All thread locker specifications per gear set manufacturer instructions must be followed
5. New differential fluid must be changed after 500-mile break-in period

Verification

• Check for leaks around differential cover, pinion seal, and axle seals after initial start-up and test drive
• Verify smooth operation with no whine, growl, or clunking noises during test drive at various speeds and loads
• Confirm proper backlash (0.005-0.009 inches) was set during assembly and documented
• Verify gear contact pattern was centered on tooth face before final assembly
• Ensure differential fluid level is at the bottom of the fill hole
• Confirm all fasteners are torqued to specification, including carrier cap bolts, cover bolts, driveshaft straps, and wheel lug nuts
• After 500-mile break-in, change differential fluid and inspect drain plug for metal debris (light metallic dust is normal; chunks or large amounts indicate problems)

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