Complete rebuild of the rear differential assembly, including disassembly, inspection, bearing and seal replacement, gear setup, and reassembly with proper backlash and preload adjustments.

Warnings

Tools required

Parts

• Rear differential rebuild kit (bearings, seals, shims) × 1 — Use OEM specification
• Pinion seal × 1 — Use OEM specification
• Pinion bearing set (inner and outer) × 1 — Use OEM specification
• Carrier bearing set × 1 — Use OEM specification
• Differential cover gasket or RTV sealant × 1 — Hyundai Genuine RTV or equivalent
• Drain plug washer × 1 — Use OEM specification
• Crush sleeve (collapsible spacer) × 1 — Use OEM specification
• Ring gear bolts × 10 — Use OEM specification
• Pinion nut × 1 — Use OEM specification
• Shim set (pinion depth adjustment) × 1 — Use OEM specification

Fluids

• 75W-90 GL-5 Gear Oil — 2 qt

Preparation

1. Park vehicle on level ground and set parking brake firmly
2. Loosen wheel lug nuts while vehicle is on ground
3. Raise vehicle and support securely on jack stands at manufacturer lift points
4. Remove both rear wheels and set aside
5. Place drain pan under rear differential
6. Clean exterior of differential housing thoroughly to prevent contamination during disassembly
7. Mark driveshaft and companion flange relationship for proper reassembly alignment
8. Photograph or diagram all component positions before disassembly

Procedure

1. 1

   Drain differential and remove cover
   Remove drain plug with 17mm socket and drain all gear oil into pan. Once drained, remove differential cover bolts in cross pattern. Carefully pry cover off using plastic pry tool, taking care not to damage housing sealing surface. Clean all old RTV or gasket material from cover and housing using plastic scraper and solvent.
   Torque spec

   Drain Plug41 Nm (30 lb-ft)
2. 2

   Remove driveshaft and axle shafts
   Mark relationship between driveshaft and pinion flange. Remove driveshaft U-joint strap bolts and separate driveshaft, securing it out of the way. Remove CV axle shaft bolts from both sides and carefully pull axle shafts from differential. Support axle shafts to prevent damage to boots.
   Torque spec

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

   CV Bolts61 Nm (45 lb-ft)
3. 3

   Measure and record original backlash
   Install dial indicator on housing with plunger perpendicular to ring gear tooth. Hold pinion stationary and rock ring gear back and forth, recording backlash reading at 4 equally-spaced points around ring gear. Typical specification is 0.10-0.18mm (0.004-0.007 inches). Record these values for comparison during reassembly.
4. 4

   Mark and remove bearing caps
   Mark bearing caps and housing with punch marks for proper reassembly orientation. Remove bearing cap bolts and carefully remove bearing caps. If using differential spreader, install it now before removing carrier assembly. Slowly spread housing just enough to remove carrier (maximum 0.5mm spread). Remove carrier assembly with ring gear attached. Remove spreader immediately to prevent housing distortion.
   ⚠Never spread differential housing more than 0.5mm or permanent distortion will occur. Use spreader with extreme care.
5. 5

   Remove and inspect pinion assembly
   Mark pinion nut position relative to pinion shaft. Using pinion holding tool, remove pinion nut. Remove companion flange using appropriate puller. Carefully tap pinion shaft out from rear of housing. Remove pinion from front, catching inner bearing, crush sleeve, and shims. Measure and record original pinion depth shim thickness for reference. Inspect pinion gear teeth for wear, scoring, or pitting.
   ℹ️Original pinion depth shim thickness is critical reference for reassembly. Measure carefully with micrometer and record.
6. 6

   Remove bearings and races
   Remove pinion bearing outer races from housing using brass drift and hammer, working around circumference evenly. Press or drive inner pinion bearings from pinion shaft using appropriate press plates or bearing separator. Remove carrier bearing races from housing using puller or drift. Press carrier bearings off carrier using press with proper support plates. Inspect all bearing surfaces, races, and housing bores for damage or wear.
7. 7

   Inspect and measure all components
   Thoroughly clean all parts in solvent and dry completely. Inspect ring gear and pinion teeth for wear patterns, scoring, pitting, or cracks. Check housing for cracks, especially around bearing bores. Measure ring gear runout (should be less than 0.08mm). Inspect differential case and spider gears for wear. Replace any worn or damaged components. If ring and pinion show wear, both must be replaced as matched set.
   ⚠Ring and pinion gears are matched sets and must be replaced together. Never replace only one component.
8. 8

   Install new pinion bearing races
   Using bearing race installer and press or driver, install new pinion bearing outer races into housing. Ensure races are fully seated and square in bores. Install new pinion bearings onto pinion shaft using press with appropriate support plates. Do not press on bearing cages, only on inner races. Lubricate bearings with gear oil before installation.
9. 9

   Set pinion depth
   Install original pinion depth shim as starting point (adjust based on markings on new pinion if provided). Install rear pinion bearing, pinion (without seal), front bearing, and companion flange temporarily without crush sleeve. Install old pinion nut and tighten to take up endplay. Use dial indicator on housing and measure pinion gear position relative to ring gear centerline. Adjust shim thickness as needed. Typical tolerance is ±0.05mm from specification marked on ring gear set.
   ℹ️Pinion depth adjustment is critical for proper gear contact pattern. New gear sets typically have variance numbers stamped on them indicating required shim adjustment from nominal.
10. 10

    Install pinion with preload setting
    Remove pinion assembly and install new pinion seal using seal driver. Reassemble pinion with correct depth shim, rear bearing, NEW crush sleeve, front bearing, companion flange, and NEW pinion nut. While holding companion flange, tighten pinion nut gradually in small increments, checking rotating torque frequently with inch-pound torque wrench. Target preload is 15-25 inch-pounds for new bearings. Once crush sleeve collapses to achieve correct preload, do not loosen nut or procedure must be restarted with new crush sleeve.
    ⚠️Never back off pinion nut to reduce preload. If preload is excessive, you must disassemble and install new crush sleeve. Reusing collapsed crush sleeve will result in bearing failure.
11. 11

    Install carrier bearings and prepare carrier
    Press new carrier bearings onto carrier assembly using press with proper support plates. If ring gear was removed, install it now with NEW ring gear bolts, tightening in star pattern to specification (verify OEM torque specification for ring gear bolts - typically 100-120 Nm). Install carrier bearing shims on both sides of carrier, starting with original thickness as baseline.
12. 12

    Install carrier and set backlash
    Install carrier bearing races if not already in housing. Carefully install carrier assembly into housing (use differential spreader if needed, following same precautions as removal). Install bearing caps in original orientation per match marks. Tighten cap bolts to specification. Install dial indicator and measure backlash at multiple points around ring gear. Adjust backlash by moving shims from one side to other (moving shim from right to left decreases backlash; left to right increases backlash). Target backlash is 0.10-0.18mm with less than 0.05mm variance around gear.
13. 13

    Check gear contact pattern
    Apply thin coat of gear marking compound to 8-10 ring gear teeth. Rotate pinion through mesh while applying light resistance to ring gear (simulate drive side load), then reverse (coast side). Examine tooth contact pattern. Proper pattern shows contact centered on tooth face, avoiding toe and heel edges. If pattern is incorrect, adjust by changing pinion depth shim (toward heel = decrease shim; toward toe = increase shim) or backlash (toward root = increase backlash; toward top = decrease backlash). Repeat until pattern is correct on both drive and coast sides.
    ℹ️Achieving proper gear contact pattern may require multiple iterations of pinion depth and backlash adjustment. Do not skip this step as improper contact will cause noise and premature failure.
14. 14

    Install differential cover and refill
    Clean cover and housing sealing surfaces thoroughly with brake cleaner. Apply continuous 3mm bead of RTV sealant to cover, circling inside of bolt holes. Install cover and tighten bolts in cross pattern to specification. Allow RTV to cure for 30 minutes before filling. Install new drain plug washer and install drain plug. Remove fill plug and add 75W-90 GL-5 gear oil until level reaches bottom of fill hole (approximately 2.0 quarts). Install fill plug with new washer.
    Torque spec

    Cover Bolts34 Nm (25 lb-ft)

    Drain Plug41 Nm (30 lb-ft)

    Fill Plug41 Nm (30 lb-ft)
15. 15

    Reinstall axles and driveshaft
    Install CV axle shafts into differential, ensuring they fully seat into side gears. Install CV bolts and tighten to specification in cross pattern. Align driveshaft to companion flange using original alignment marks. Install U-joint strap bolts and tighten evenly to specification. Rotate driveshaft by hand to verify smooth operation with no binding or unusual noise.
    Torque spec

    CV Bolts61 Nm (45 lb-ft)

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

Reassembly

1. Install rear wheels and hand-tighten lug nuts
2. Lower vehicle to ground and torque wheel lug nuts to specification in star pattern
3. Test drive vehicle at low speeds initially, listening for any abnormal whine, grinding, or vibration
4. After 50-100 miles of break-in driving, recheck differential fluid level and inspect cover for leaks
5. Avoid heavy acceleration or towing during first 500 miles to allow gears to properly seat

Verification

• Check for fluid leaks around differential cover, pinion seal, and axle seals after test drive
• Verify smooth, quiet operation with no whine or growling during acceleration and deceleration
• Confirm no excessive heat build-up in differential housing after 15-20 minute drive
• Recheck all fastener torques after initial test drive
• Verify backlash is still within specification after break-in period if any noise develops

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