This procedure drains and refills the rear differential fluid on the 2016-2024 Hyundai Tucson AWD, ensuring proper lubrication and longevity of the differential components.

Warnings

Tools required

Parts

• Drain plug crush washer × 1 — Use OEM specification
• Fill plug crush washer × 1 — Use OEM specification

Fluids

• 75W-90 GL-5 Gear Oil — 2 qt

Preparation

1. Park vehicle on level surface and engage parking brake
2. Place wheel chocks in front of front wheels
3. Allow differential to cool if recently driven (approximately 30 minutes)
4. Raise rear of vehicle and support securely on jack stands at manufacturer-approved lift points
5. Locate the rear differential beneath the vehicle - it is centered between the rear wheels
6. Clean area around drain and fill plugs with wire brush to prevent contamination

Procedure

1. 1

   Locate and remove fill plug
   Identify the fill plug on the front face of the rear differential housing. Using a 17mm socket, loosen and remove the fill plug first to ensure it can be removed before draining. This prevents being unable to refill if the fill plug is seized.
2. 2

   Position drain pan and remove drain plug
   Place drain pan beneath the rear differential drain plug (located on the bottom or rear of the differential housing). Using a 17mm socket, carefully loosen and remove the drain plug. Allow fluid to drain completely into the pan. Inspect drained fluid for metal particles or contamination - excessive debris may indicate wear issues.
3. 3

   Inspect and clean drain plug
   Examine the drain plug for damage to the threads or magnetic tip. Wipe clean with a lint-free cloth and inspect the condition of the crush washer sealing surface. Remove and discard the old crush washer.
4. 4

   Reinstall drain plug with new washer
   Install a new crush washer onto the drain plug. Thread the drain plug into the differential housing by hand to avoid cross-threading, then tighten to specification using a torque wrench.
   Torque spec

   Drain Plug41 Nm (30 lb-ft)
5. 5

   Fill differential with gear oil
   Using a fluid pump or squeeze bottle with extension tube, insert the nozzle into the fill plug hole. Add 75W-90 GL-5 gear oil slowly until fluid begins to drip from the fill hole, indicating proper level. The rear differential capacity is 2.0 quarts. Allow a few moments for fluid to settle and top off if necessary.
6. 6

   Install fill plug with new washer
   Install a new crush washer onto the fill plug. Thread the fill plug into the differential housing by hand, then tighten to specification using a torque wrench.
   Torque spec

   Fill Plug41 Nm (30 lb-ft)
7. 7

   Clean and inspect for leaks
   Wipe any spilled gear oil from the differential housing. Inspect both drain and fill plugs for proper seating and initial signs of leakage. Lower vehicle from jack stands.

Reassembly

1. Remove jack stands and lower vehicle to ground
2. Properly dispose of used gear oil at a recycling facility or auto parts store
3. Store remaining new gear oil in a sealed container for future use

Verification

• Start engine and drive vehicle forward and backward several feet to circulate new fluid
• Re-inspect drain and fill plugs for leaks after initial test drive
• After 50-100 miles of driving, re-check differential for any signs of leakage around plugs
• Record mileage and date of service for maintenance tracking

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