This procedure covers the removal, inspection, and replacement of the rear differential assembly on a 2016-2024 Hyundai Tucson with the 2.5L I4 AWD engine, including draining and refilling the differential fluid.

Warnings

Tools required

Parts

• Rear differential assembly (if replacing complete unit) × 1 — Use OEM specification
• Differential cover gasket × 1 — Use OEM gasket or RTV sealant per specification
• Drain plug washer × 1 — Use OEM specification
• Axle nut cotter pins × 2 — OEM or equivalent
• Driveshaft U-joint strap bolts (if corroded) × 4 — Use OEM specification

Fluids

• 75W-90 GL-5 Gear Oil — 2 qt

Preparation

1. Park vehicle on level surface and apply parking brake firmly
2. Place wheel chocks in front of front wheels
3. Raise rear of vehicle and support securely on jack stands at manufacturer-recommended jacking points
4. Remove both rear wheels
5. If replacing internal components only, allow differential to cool completely before draining fluid

Procedure

1. 1

   Remove rear axle nuts
   Remove the cotter pins from both rear axle nuts using diagonal cutters or cotter pin remover. Using a 32mm or 33mm socket with breaker bar, loosen and remove both rear axle nuts. These are torqued to 250 Nm and may require significant force to break loose.
   Torque spec

   Axle Nut250 Nm (184 lb-ft)
2. 2

   Disconnect rear axle shafts from differential
   Mark the position of the CV joint flanges relative to the differential output flanges using a paint pen or marker. Remove the CV bolts (typically 6 bolts per side) connecting each rear axle shaft to the differential output flanges. Support the axle shafts with wire or zip ties to prevent them from hanging and damaging CV boots.
   Torque spec

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

   Mark and disconnect rear driveshaft
   Mark the alignment of the rear driveshaft flange to the differential input flange using paint or a center punch. Remove the four U-joint strap bolts securing the driveshaft to the differential pinion flange. Support the driveshaft and carefully lower it away from the differential, securing it to the exhaust or chassis with wire to prevent it from dropping.
   ⚠Driveshaft must be reinstalled in the exact same orientation to prevent driveline vibration. Verify alignment marks are clearly visible.
   Torque spec

   Driveshaft U-Joint Straps20 Nm (15 lb-ft)
4. 4

   Drain differential fluid
   Position a drain pan with at least 3-quart capacity beneath the differential. Remove the differential drain plug located at the bottom of the housing and allow all fluid to drain completely (approximately 2 quarts). If no drain plug is present, proceed to remove the differential cover bolts and carefully pry the cover loose, allowing fluid to drain. Inspect drained fluid for metal particles or contamination.
   ⚠Fluid may drain rapidly once cover is removed. Position drain pan to capture all fluid.
5. 5

   Remove differential cover (if applicable)
   Remove all differential cover bolts in a crisscross pattern. Carefully pry the cover away from the housing using a pry bar at designated pry points. Remove the old gasket material from both the cover and housing using a razor blade scraper and wire brush. Inspect the inside of the differential housing for metal shavings, damaged gears, or bearing debris.
   Torque spec

   Differential Cover Bolts35 Nm (26 lb-ft)
6. 6

   Support differential assembly
   Position a transmission jack or adjustable jack stand beneath the center of the differential housing. Raise the jack until it just contacts the differential and provides secure support. Ensure the differential is balanced and stable on the jack before proceeding.
   ⚠️Differential assembly weighs 50-60 lbs and will fall once mounting bolts are removed. Ensure jack is securely positioned and stable.
7. 7

   Disconnect differential mounting points
   Locate and remove all differential mounting bolts connecting the assembly to the rear subframe or crossmember. Typical configuration includes 4-6 mounting bolts. Remove bolts in a sequential pattern to maintain balance. Note the location of any spacers, shims, or alignment dowels for reinstallation.
   Torque spec

   Mounting Bolts27 Nm (20 lb-ft)
8. 8

   Remove differential assembly
   With all mounting points disconnected, carefully lower the transmission jack to remove the differential assembly from the vehicle. Guide the differential past any obstructions including exhaust components, suspension arms, and chassis braces. Once clear, transfer the assembly to a clean workbench for further service or replacement.
   ⚠Ensure all connections are disconnected before lowering. Check for any brake line brackets, ABS sensor wires, or vent hoses that may still be attached.
9. 9

   Inspect and service or replace differential
   If replacing the complete differential, transfer any necessary brackets, sensors, or mounting hardware from the old unit to the new one. If servicing the existing differential, replace bearings, seals, gears, or other worn components as needed. Clean all mating surfaces thoroughly and install a new gasket or apply RTV sealant per manufacturer specifications to the differential cover.
   Torque spec

   Differential Cover Bolts35 Nm (26 lb-ft)
10. 10

    Install differential assembly
    Position the differential assembly (new or serviced) onto the transmission jack and raise it into position beneath the vehicle. Align the differential with the mounting points on the subframe, ensuring any alignment dowels or shims are properly positioned. Start all mounting bolts by hand, then torque to specification in a crisscross pattern.
    Torque spec

    Mounting Bolts27 Nm (20 lb-ft)
11. 11

    Reconnect rear driveshaft
    Guide the rear driveshaft into position and align the previously made alignment marks on the driveshaft flange and differential pinion flange. Install the U-joint strap bolts and tighten evenly in a crisscross pattern to the specified torque. Verify the driveshaft rotates freely without binding.
    Torque spec

    Driveshaft U-Joint Straps20 Nm (15 lb-ft)
12. 12

    Reconnect rear axle shafts
    Align the rear axle shaft CV joint flanges with the differential output flanges using the alignment marks made during disassembly. Install all CV bolts and tighten to specification in a star pattern. Ensure the axle shafts are properly seated and rotate freely.
    Torque spec

    CV Bolts61 Nm (45 lb-ft)
13. 13

    Fill differential with gear oil
    Using a fluid transfer pump, add 2.0 quarts of 75W-90 GL-5 gear oil through the differential fill plug opening (typically located on the side or top of the housing). Fill until fluid begins to drip from the fill hole, indicating proper level. Install the fill plug with a new washer if applicable. If the differential cover was removed, ensure it is properly installed with new gasket before filling.
    Torque spec

    Cover Screws11 Nm (8 lb-ft)
14. 14

    Install rear axle nuts
    Install new rear axle nuts onto both axle shafts. Torque each axle nut to 250 Nm (184 lb-ft) using a torque wrench. Install new cotter pins through the axle nut castellations and bend the pins to secure. If the axle nut design uses staking instead of cotter pins, stake the nut collar into the axle shaft groove using a punch.
    ⚠Never reuse old cotter pins. Always use new cotter pins or properly stake the axle nut per manufacturer specifications.
    Torque spec

    Axle Nut250 Nm (184 lb-ft)
15. 15

    Reinstall wheels and lower vehicle
    Install both rear wheels and hand-tighten all lug nuts. Lower the vehicle until the wheels just contact the ground. Torque all lug nuts to 140 Nm (103 lb-ft) in a star pattern. Fully lower the vehicle and remove jack stands. Remove wheel chocks.
    Torque spec

    Wheel Lug Nuts140 Nm (103 lb-ft)

Reassembly

1. Double-check that all fasteners are torqued to specification, particularly axle nuts, CV bolts, and driveshaft straps
2. Verify differential fluid level is correct by checking that fluid drips from fill hole when plug is removed
3. Ensure all alignment marks on driveshaft and axle shafts were properly matched during installation

Verification

• Start the engine and shift through all gear positions including reverse to circulate differential fluid
• Test drive the vehicle at various speeds, listening for abnormal noises from the rear differential area
• Check for fluid leaks around the differential cover, drain plug, axle seals, and pinion seal after test drive
• Verify smooth operation with no vibration, which would indicate misaligned driveshaft or axle shafts
• After 50-100 miles of driving, recheck differential fluid level and inspect all connection points for leaks

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