This procedure drains and refills the front differential fluid on AWD 2016-2024 Hyundai Tucson models equipped with the 2.5L I4 engine, requiring removal of the fill and drain plugs.

Warnings

Tools required

Parts

• Front differential drain plug washer × 1 — Use OEM specification or consult dealer
• Front differential fill plug washer × 1 — Use OEM specification or consult dealer

Fluids

• 75W-90 GL-5 Gear Oil — 1.5 qt

Preparation

1. Park vehicle on level ground and engage parking brake
2. Place wheel chocks behind rear wheels
3. Allow differential to cool to warm (not hot) temperature if recently driven
4. Raise front of vehicle and secure on jack stands rated for vehicle weight
5. Locate front differential on front axle assembly between the two front wheels
6. Identify fill plug (upper location on differential housing) and drain plug (lower location)
7. Verify you have the correct 75W-90 GL-5 gear oil (1.5 quarts minimum)

Procedure

1. 1

   Remove fill plug first
   Using a 24mm socket or wrench, loosen and remove the upper fill plug from the front differential housing. This ensures you can refill the differential after draining. If the fill plug cannot be removed, do not proceed with draining. Clean the plug and inspect the washer for damage.
2. 2

   Position drain pan
   Place an oil drain pan with at least 2-quart capacity directly beneath the front differential drain plug (lower plug on housing). Position the pan to catch fluid that may spray initially when plug is removed.
3. 3

   Remove drain plug and drain fluid
   Using a 24mm socket or wrench, carefully loosen the drain plug. Remove the plug completely and allow all fluid to drain into the pan. The differential should drain approximately 1.5 quarts. Allow at least 10-15 minutes for complete drainage. Inspect drained fluid for metal particles or contamination.
4. 4

   Clean and reinstall drain plug
   Clean the drain plug threads with a wire brush and wipe the differential housing drain hole area clean. Replace the drain plug washer with a new one. Thread the drain plug in by hand first to avoid cross-threading, then tighten to specification using a torque wrench.
   Torque spec

   Mounting Bolts27 Nm (20 lb-ft)
5. 5

   Fill differential with new gear oil
   Using a fluid pump or squeeze bottle, insert the nozzle into the fill plug hole. Slowly pump in 75W-90 GL-5 gear oil until fluid begins to seep out of the fill hole. The differential is full when fluid reaches the bottom of the fill plug threads. This should take approximately 1.5 quarts.
6. 6

   Reinstall fill plug
   Wipe away any excess gear oil from around the fill hole. Replace the fill plug washer with a new one. Thread the fill plug in by hand to avoid cross-threading, then tighten to specification using a torque wrench.
   Torque spec

   Mounting Bolts27 Nm (20 lb-ft)
7. 7

   Clean up and lower vehicle
   Wipe down the differential housing to remove any spilled gear oil. Check both plugs to ensure they are secure with no leaks visible. Carefully lower the vehicle from jack stands to the ground.

Reassembly

1. No disassembly was required for this procedure beyond plug removal
2. Ensure both fill and drain plugs are torqued properly with new washers installed
3. Dispose of used gear oil properly at a recycling center or auto parts store

Verification

• Start the vehicle and allow it to idle for 1-2 minutes
• With the vehicle still on level ground, check underneath for any signs of leakage around the fill and drain plugs
• Take a short test drive (5-10 minutes) and recheck for leaks after returning
• Monitor for any unusual noises from the front differential during normal driving over the next few days
• Verify proper AWD operation by testing on a safe surface if conditions allow

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