Differential Rebuild - Rear

Complete disassembly, inspection, and rebuild of the rear differential assembly including bearing replacement, gear setup, and proper backlash/preload adjustment.

Warnings

Tools required

Parts

• Differential bearing overhaul kit (includes pinion bearings, carrier bearings, seals, crush sleeve) × 1 — Dana 44 overhaul kit for Viper
• Pinion seal × 1 — Use OEM specification
• Pinion nut × 1 — Use OEM specification (one-time use)
• Ring gear bolts (if reusing gear) × 10 — Use OEM specification
• Differential cover gasket or RTV sealant × 1 — Use OEM specification
• Driveshaft bolts (if replacing) × 4 — Use OEM specification
• Gear marking compound × 1 — Prussian blue
• Limited-slip clutch pack (if worn) × 1 — Dana 44 limited-slip clutches
• Shim kit for pinion depth adjustment × 1 — Dana 44 pinion shim set

Fluids

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

Preparation

1. Park vehicle on level surface and engage parking brake.
2. Loosen rear wheel lug nuts while vehicle is on ground.
3. Raise rear of vehicle and support securely on jack stands positioned under frame rails.
4. Remove both rear wheels.
5. Place drain pan under differential.
6. Mark driveshaft and differential yoke position for proper reassembly alignment.
7. Have all specialized tools and parts ready before disassembly, as differential should not sit partially assembled for extended periods.

Procedure

1. 1

   Drain Differential Fluid
   Locate drain plug on bottom of differential housing. Remove drain plug using appropriate wrench and allow gear oil to drain completely into drain pan. Inspect drained fluid for metal particles, which indicate gear or bearing wear. If drain plug has metal particles attached to magnetic tip, this is normal but excessive chunks indicate damage.
2. 2

   Remove Driveshaft
   Remove the 4 bolts securing driveshaft U-joint to differential yoke. Support driveshaft and carefully slide it rearward to separate from differential. Do not allow driveshaft to hang unsupported. Secure driveshaft out of work area or remove completely if necessary.
3. 3

   Remove Axle Shafts
   Remove brake calipers and secure out of the way without disconnecting brake lines. Remove brake rotors. At each hub, if equipped, remove the cotter pin and axle nut per factory service manual procedure for the Viper IRS. The 1992 Viper uses independent rear suspension with half-shafts. Remove the bolts securing each half-shaft/CV joint flange to the differential output flanges (verify exact count against factory service manual). Carefully pull axle shafts out from differential and support them to prevent CV joint damage.
4. 4

   Remove Differential Cover
   Remove differential cover bolts in a crisscross pattern to prevent warping. Carefully pry cover off using a soft pry bar if stuck. Remove and discard gasket or old RTV sealant. Inspect internal components for visible damage, unusual wear patterns, or metal debris.
5. 5

   Mark and Measure Gear Setup
   Before disassembly, measure and record ring gear backlash using dial indicator at 4 points around the ring gear (rotate 90 degrees between measurements). Record these values for reference during reassembly. Use paint marker to mark carrier bearing cap orientation and position relative to housing. Mark ring gear position relative to carrier if reusing gears.
6. 6

   Remove Carrier Assembly
   Remove carrier bearing cap bolts. Note that carrier bearing caps may be numbered or marked for position. Carefully pry carrier assembly with ring gear out of housing using pry points. The carrier bearings will remain on the carrier. Place assembly on clean workbench for disassembly.
7. 7

   Remove Pinion Nut and Yoke
   Using pinion holding tool to prevent rotation, remove pinion nut with impact wrench or breaker bar. Note: this nut achieves very high torque and requires significant force to remove. Mark pinion yoke position on pinion shaft. Use puller to remove yoke from pinion shaft. Remove pinion seal and discard.
8. 8

   Remove Pinion Assembly
   Carefully tap pinion shaft from rear of housing using soft-face hammer. Pinion will come out with front bearing, inner rear bearing race, and crush sleeve (if equipped). Catch pinion to prevent dropping. Remove front pinion bearing and crush sleeve from pinion shaft. Remove rear pinion bearing cone from pinion shaft using bearing separator and press or puller.
9. 9

   Remove Bearing Races
   Using brass drift and hammer, carefully drive front and rear pinion bearing races out of housing. Drive evenly around race to prevent cocking. Remove carrier bearing cones from carrier using bearing separator and press. Keep bearings organized and labeled if measuring for reference.
10. 10

    Disassemble Carrier
    If ring gear is being replaced or carrier needs inspection, remove ring gear bolts (standard right-hand thread on Dana 44). Use soft-face hammer to tap ring gear off carrier. Disassemble differential carrier by removing pinion shaft lock bolt and pinion shaft. Remove spider gears, side gears, and thrust washers. If equipped with limited-slip differential, carefully disassemble clutch pack assembly, noting exact order and orientation of all components.
11. 11

    Clean and Inspect All Components
    Thoroughly clean all components with brake cleaner or solvent. Inspect ring and pinion gear teeth for pitting, scoring, excessive wear, or chipping. Inspect carrier housing and differential housing for cracks or damage. Check all bearing surfaces for wear. Inspect limited-slip clutch plates (if equipped) for wear, glazing, or damage. Replace any worn or damaged components. Clean all old sealant from housing and cover mating surfaces.
12. 12

    Install New Bearing Races
    Install new front and rear pinion bearing races into housing using bearing race installer and driver set. Drive races fully seated until they bottom in housing. Install new carrier bearing races onto carrier using press or driver set, ensuring they are fully seated against shoulders.
13. 13

    Determine Pinion Depth
    Use pinion depth gauge tool set to determine correct shim thickness for pinion depth setting. This critical measurement establishes pinion gear mesh position. Install gauge block in differential housing with front and rear pinion bearings (without seals). Follow gauge tool instructions to measure and calculate required shim thickness. Pinion depth is typically marked on pinion head (e.g., +2, -1) indicating variance from nominal in thousandths of inch. Select shim pack that achieves specification when combined with pinion marking.
14. 14

    Assemble and Install Pinion
    Install selected pinion depth shim on pinion shaft. Press new rear pinion bearing cone onto pinion shaft using bearing installer and press. Install pinion into housing from rear. Install new crush sleeve (or solid spacer if specified) onto pinion shaft. Install front pinion bearing onto shaft. Install pinion yoke, aligning with previous marks if reusing. Install new pinion seal into housing using seal driver.
15. 15

    Set Pinion Bearing Preload
    Install new pinion nut. Using pinion holding tool and torque wrench, tighten pinion nut gradually while checking pinion bearing preload. Proper preload for new bearings is typically 15-25 inch-pounds of rotational drag, measured with inch-pound torque wrench on pinion nut (rotating pinion, not breaking-torque). Tighten in small increments, checking frequently. Do not overtighten as crush sleeve cannot be reused if preload is exceeded. If preload is exceeded, crush sleeve must be replaced and process repeated.
16. 16

    Reassemble Carrier (if disassembled)
    If carrier was disassembled, reassemble in reverse order. Install side gears with thrust washers into carrier. Install spider gears and align with pinion shaft holes. Install pinion shaft and secure with lock bolt (apply thread locker). For limited-slip differentials, reassemble clutch pack in exact original order and orientation. If installing ring gear, heat gear to approximately 200°F to ease installation, align with carrier, and install new ring gear bolts. Torque ring gear bolts in star pattern to specification (verify exact value against factory service manual; Dana 44 ring gear bolts are commonly in the 90-100 ft-lb range).
17. 17

    Install Carrier Assembly and Set Backlash
    Install carrier bearing adjusters or shims on both sides of carrier. Install carrier assembly into housing. Install bearing caps in correct orientation (matching marks made during disassembly). Install cap bolts finger-tight initially. Using side bearing adjuster tool and dial indicator mounted to ring gear tooth, adjust carrier bearing preload and ring gear backlash simultaneously. Proper backlash is typically 0.005-0.008 inches, measured at ring gear with pinion held stationary. Tighten bearing caps evenly while maintaining backlash specification. Carrier bearing preload should result in additional rotational drag beyond pinion preload.
18. 18

    Check Gear Contact Pattern
    Apply thin coat of gear marking compound to several ring gear teeth. Rotate pinion through several revolutions in both directions under light resistance (use shop rag on yoke for drag). Examine contact pattern on ring gear teeth. Proper pattern should be centered on tooth face, slightly toward toe. Drive side and coast side patterns should be similar and well-centered. If pattern is incorrect, adjust by changing pinion depth shims (moves pattern up/down tooth) or backlash adjustment (moves pattern toward toe/heel). Repeat until satisfactory pattern is achieved.
19. 19

    Final Preload and Backlash Verification
    Verify final backlash is within 0.005-0.008 inch specification at multiple points around ring gear. Check total bearing preload (pinion plus carrier) by measuring rotational torque at pinion nut - should be 25-35 inch-pounds for new bearings. Torque carrier bearing cap bolts to final specification per factory service manual (value must be verified for this axle). Re-check backlash after final torquing to ensure it did not change.
20. 20

    Install Differential Cover
    Clean cover and housing mating surfaces thoroughly. Apply continuous bead of RTV silicone sealant to cover or install new gasket per manufacturer specification. Install cover and bolts, torquing in crisscross pattern to specification. Allow RTV to cure per manufacturer instructions before filling with fluid.
21. 21

    Install Axle Shafts
    Install axle shafts into differential output flanges, ensuring splines engage properly. Install CV joint bolts and torque to specification in star pattern. Install new axle nuts and torque to specification. Install new cotter pins. Install brake rotors and calipers.
22. 22

    Install Driveshaft
    Align driveshaft yoke with differential yoke using marks made during disassembly. Install driveshaft bolts and torque in crisscross pattern to specification.
23. 23

    Fill Differential
    Locate fill plug on differential housing (typically on passenger side). Remove fill plug. Using fluid pump, fill differential with the specified capacity of 75W-90 GL-5 gear oil (verify exact capacity against factory service manual; Dana 44-class units are typically around 2 to 2.5 quarts). For limited-slip equipped differentials (standard on Viper), add appropriate amount of limited-slip additive per manufacturer specification. Fill until fluid reaches bottom of fill hole. Install fill plug and torque to specification.
24. 24

    Install Wheels and Lower Vehicle
    Install rear wheels and hand-tighten lug nuts. Lower vehicle to ground. Torque lug nuts to specification in star pattern.

Reassembly

1. Reassembly is detailed in steps above as this is a rebuild procedure requiring specific assembly sequence.
2. Critical torque specifications must be followed exactly, particularly for pinion preload and carrier bearing adjustment.
3. Gear contact pattern must be verified before final assembly to ensure proper gear mesh and longevity.
4. RTV sealant must cure fully (typically 24 hours) before driving vehicle to prevent leaks.

Verification

• Start engine and verify no unusual noises from differential.
• With vehicle on lift and wheels off ground, shift transmission through gears and verify smooth operation and proper engagement.
• Check for leaks around differential cover, pinion seal, and axle seals after engine run.
• Test drive vehicle starting gently. Listen for whine, howl, or clunking from differential.
• Perform figure-eight maneuvers in parking lot to verify limited-slip operation (both wheels should drive through turns).
• After 50-100 miles, re-check differential fluid level and inspect for leaks. Some breaking-in noise is normal with new gears but should diminish.
• Re-check fluid level and condition after 500 miles of break-in driving.

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