Complete disassembly, inspection, and rebuild of the front differential assembly on AWD 2.5L Tucson models, including bearing and seal replacement.

Warnings

Tools required

Parts

• Front differential overhaul kit with bearings and seals × 1 — Use OEM specification
• Pinion bearing set (if applicable) × 1 — Use OEM specification
• Differential side bearing set × 1 — Use OEM specification
• Pinion seal × 1 — Use OEM specification
• Drain plug washer × 1 — Use OEM specification
• Fill plug washer × 1 — Use OEM specification
• RTV silicone sealant (Hyundai approved) × 1 — Use OEM specification
• Axle nut cotter pin or staking material × 2 — Use OEM specification
• Shim kit for bearing preload adjustment × 1 — Use OEM specification

Fluids

• 75W-90 GL-5 Gear Oil — 2 qt

Preparation

1. Lift vehicle on a four-post lift or secure on jack stands at all four corners
2. Remove front wheels and set aside in safe location
3. Place drain pan under front differential assembly
4. Remove drain plug and completely drain front differential fluid
5. Clean exterior of differential housing with brake cleaner to prevent contamination during disassembly
6. Disconnect negative battery terminal if equipped with electronic differential control
7. Take photographs of component positioning before disassembly for reference

Procedure

1. 1

   Remove front axle shafts
   Remove both front axle nuts after unstaking or removing cotter pins. Support lower control arms and remove wheel speed sensor connectors if interfering. Remove CV joint-to-differential bolts on both sides and carefully withdraw axle shafts from differential housing. Support axle shafts with wire to prevent damage to CV boots.
   Torque spec

   Axle Nut250 Nm (184 lb-ft)

   CV Bolts61 Nm (45 lb-ft)
2. 2

   Remove differential cover
   Remove all differential cover bolts in a crossing pattern to avoid warping the cover. Carefully pry cover loose using plastic wedges at designated pry points. Remove cover and gasket/RTV residue. Inspect internal components for obvious damage, metal shavings, or excessive wear before proceeding.
   Torque spec

   Cover Bolts34 Nm (25 lb-ft)
3. 3

   Mark and measure existing setup
   Before disassembly, use dial indicator to measure and record ring gear backlash at four points around the gear (should be 0.13-0.18mm typically). Mark bearing caps with punch marks for orientation. Measure and record pinion bearing preload using inch-pound torque wrench (rotating torque). Apply gear marking compound to several teeth and rotate to check gear contact pattern for reference.
4. 4

   Remove differential carrier assembly
   Remove differential bearing cap bolts. Carefully pry carrier assembly outward using appropriate pry points. Remove carrier assembly with side bearings attached. Place assembly on clean workbench. Do not mix left and right bearing caps or shims.
5. 5

   Disassemble carrier and remove bearings
   Remove ring gear bolts (left-hand thread on most applications). Use bearing puller to remove side bearings from carrier. Keep shims and bearings organized by side. Remove differential pin, side gears, and pinion gears from carrier. Inspect all components for wear, scoring, or damage.
   ⚠Ring gear bolts may have left-hand threads. Verify thread direction before applying force.
6. 6

   Remove pinion gear and bearings
   Hold pinion flange with holder tool and remove pinion nut. Use puller to remove flange. Drive out pinion seal. Carefully tap pinion shaft rearward to remove from housing with inner bearing. Remove outer bearing race from housing using race driver. Remove inner bearing and note shim thickness/placement. Remove pinion depth shim from housing.
   ℹ️Record pinion shim thickness and position. This determines pinion depth and will be used as baseline for reassembly.
7. 7

   Clean and inspect all components
   Thoroughly clean housing, carrier, gears, and all components with brake cleaner. Inspect ring and pinion teeth for pitting, scoring, or excessive wear. Inspect carrier and housing bearing bores for damage. Check gear tooth contact patterns against service manual specifications. Replace ring and pinion as matched set if any damage is present. Inspect case for cracks or wear.
8. 8

   Install new pinion bearings and set depth
   Press new inner and outer pinion bearings onto pinion shaft using appropriate bearing driver. Install original pinion depth shim (or new shim if specified in overhaul kit) into housing. Drive new outer bearing race into housing until fully seated. Install pinion assembly with inner bearing into housing. Install outer bearing, new crush sleeve, and flange.
   ⚠Pinion depth shim selection is critical. Use pinion depth gauge tool if available or start with original shim thickness.
9. 9

   Set pinion bearing preload
   Install new pinion nut and tighten gradually while rotating pinion to seat bearings. Measure rotating torque with inch-pound torque wrench. Target preload is typically 10-15 in-lbs for new bearings. Tighten nut incrementally until correct preload is achieved. Do not back off nut - if exceeded, replace crush sleeve and start over.
   ⚠Crush sleeve is single-use. If pinion nut is over-tightened, sleeve must be replaced and procedure restarted.
10. 10

    Install new pinion seal
    Drive new pinion seal into housing using seal driver until flush with housing face. Lubricate seal lip with gear oil before installing flange. Ensure flange sealing surface is smooth and free of burrs.
11. 11

    Assemble differential carrier
    Install side gears and pinion gears into carrier with new thrust washers. Install differential pin and secure. Press new side bearings onto carrier using bearing driver. If reusing ring gear, clean bolt threads thoroughly. Install ring gear and torque bolts to specification in crossing pattern (verify thread direction). Install original shims on each side bearing as starting point.
12. 12

    Install carrier and set backlash
    Install carrier assembly into housing with bearing caps in marked positions. Install and finger-tighten bearing cap bolts. Use differential spreader to open housing slightly (maximum 0.25mm). Position carrier assembly and remove spreader. Tighten bearing cap bolts evenly. Measure backlash with dial indicator at ring gear. Adjust by moving shims from one side to other until backlash is 0.13-0.18mm. Moving shims from right to left decreases backlash; left to right increases backlash.
    ⚠️Do not exceed maximum spread of housing (0.25mm). Excessive spreading can crack or permanently deform housing.
13. 13

    Check gear contact pattern
    Apply thin coat of gear marking compound to several ring gear teeth. Rotate pinion in both directions while applying light resistance. Check tooth contact pattern on both drive and coast sides. Pattern should be centered on tooth with slight bias toward toe. Adjust pinion depth shim if pattern is too high or low on tooth. Adjust backlash shims if pattern is too far toward toe or heel.
    ℹ️Proper gear contact pattern is critical for quiet operation and longevity. Consult service manual for acceptable patterns.
14. 14

    Install differential cover with sealant
    Clean cover and housing mating surfaces thoroughly. Apply continuous 3mm bead of RTV sealant to cover following bolt holes on inner side. Install cover within 10 minutes of applying sealant. Install cover bolts and torque in crossing pattern to specification. Allow sealant to cure for minimum 30 minutes before filling.
    Torque spec

    Cover Bolts34 Nm (25 lb-ft)
15. 15

    Reinstall axle shafts and fill differential
    Install new axle shaft seals if not previously replaced. Carefully insert axle shafts into differential ensuring splines engage properly. Install CV joint-to-differential bolts and torque to specification. Install new drain plug washer and install drain plug to specification. Remove fill plug, install new washer. Fill differential with 1.5 quarts of 75W-90 GL-5 gear oil through fill hole until oil begins to seep out. Install fill plug and torque to specification.
    Torque spec

    CV Bolts61 Nm (45 lb-ft)

    Drain Plug41 Nm (30 lb-ft)

    Fill Plug41 Nm (30 lb-ft)
16. 16

    Reinstall wheels and final checks
    Install front wheels and torque lug nuts to specification in star pattern. Install new axle nut and torque to specification. Install new cotter pin or stake nut as applicable. Reconnect battery if disconnected. Lower vehicle to ground.
    Torque spec

    Wheel Lug Nuts140 Nm (103 lb-ft)

    Axle Nut250 Nm (184 lb-ft)

Reassembly

1. Ensure all torque specifications have been met, particularly axle nuts, CV bolts, and differential cover bolts
2. Verify RTV sealant has cured for at least 30 minutes before test driving
3. Double-check that drain and fill plugs are tight with new washers installed
4. Confirm gear oil level is correct (oil should be at bottom of fill hole)

Verification

• Test drive vehicle at various speeds listening for whining, howling, or grinding noises from front differential
• Check for fluid leaks around differential cover, pinion seal, and axle seals after test drive
• Verify smooth operation during acceleration and deceleration with no vibration or binding
• Recheck fluid level after test drive and top off if necessary
• Monitor differential for first 500 miles for any unusual noises or leaks
• Consider changing differential fluid at 500 miles to remove any break-in debris

More procedures for this vehicle