This procedure covers the removal and replacement of the front differential assembly on a 2016-2021 Honda Civic 1.5L Turbo, including draining transmission fluid, disconnecting axles, and removing the differential unit.

Warnings

Tools required

Parts

• Front differential assembly × 1 — Honda OEM or Aisin replacement
• Differential mounting bolt seals × 4 — Use OEM specification
• Axle hub nuts (single-use) × 2 — 90305-T0G-A01
• Differential cover gasket or RTV sealant × 1 — Honda Bond HT or equivalent
• Drain plug washer × 1 — 94109-20000

Fluids

• Honda DW-1 ATF — 8 qt

Preparation

1. Park vehicle on level surface and apply parking brake
2. Place wheel chocks behind rear wheels
3. Loosen both front axle nuts while vehicle is on ground (do not remove)
4. Loosen front wheel lug nuts while vehicle is on ground
5. Raise front of vehicle and secure on jack stands at manufacturer-specified lift points
6. Remove both front wheels
7. Remove front engine undercovr and splash shields
8. Position drain pan under transmission drain plug

Procedure

1. 1

   Drain transmission fluid
   Locate the transmission drain plug on the bottom of the transmission case. Using a 3/8" ratchet, remove the drain plug and allow transmission fluid to drain completely into the drain pan. This may take 10-15 minutes. Remove and discard the drain plug washer.
2. 2

   Remove front axle nuts
   With the vehicle raised and secured, remove the previously loosened 32mm axle nuts from both front hubs. These nuts are single-use and must be replaced during reassembly. Set aside and do not reuse.
3. 3

   Disconnect driver side axle from differential
   Locate the six CV joint bolts connecting the inner CV joint to the differential flange on the driver side. Remove all six bolts and carefully separate the CV joint from the differential. Support the axle with wire or mechanic's wire to prevent damage. Expect additional fluid drainage.
   ⚠Additional transmission fluid will drain when the axle is disconnected. Ensure drain pan is positioned.
   Torque spec

   CV Bolts58 Nm (43 lb-ft)
4. 4

   Remove driver side axle from hub
   Push the hub inward while pulling the axle shaft outward to separate the axle from the hub bearing. If needed, use a brass drift to tap the axle end. Remove the complete axle assembly and set aside on clean surface.
5. 5

   Disconnect passenger side axle from differential
   Repeat the CV joint bolt removal process for the passenger side axle. Remove the six CV joint bolts connecting the inner CV joint to the intermediate shaft flange. Separate the CV joint and support the axle.
   Torque spec

   CV Bolts58 Nm (43 lb-ft)
6. 6

   Remove passenger side axle from hub
   Push the hub inward while pulling the axle shaft outward to separate the passenger side axle from the hub bearing. Remove the complete axle assembly and set aside.
7. 7

   Support transmission
   Position a transmission jack or engine support fixture under the transmission to support its weight. The differential provides structural support to the transmission, so the transmission must be properly supported before differential removal.
   ⚠️Failure to properly support the transmission can result in transmission damage or personal injury.
8. 8

   Remove differential cover screws
   Locate the differential cover on the driver side of the transmission. Remove all cover screws using appropriate socket. Note screw locations if they are different lengths. Carefully pry the cover away from the transmission case.
   Torque spec

   Cover Screws10 Nm (8 lb-ft)
9. 9

   Remove differential mounting bolts
   Locate the four differential mounting bolts that secure the differential assembly to the transmission case. These are typically accessible from the front and side of the differential housing. Remove all mounting bolts and their sealing washers.
   Torque spec

   Mounting Bolts26 Nm (19 lb-ft)
10. 10

    Remove differential assembly
    With all mounting bolts removed, carefully work the differential assembly out of the transmission case. The differential may require some wiggling or light prying to break it free from the transmission. Have an assistant help support the 40-50 lb assembly as it comes free. Lower the differential and remove it from under the vehicle.
11. 11

    Inspect and clean mating surfaces
    Thoroughly clean all gasket material and old sealant from the transmission case mating surface and differential cover mating surface. Inspect the transmission case opening for any damage or debris. Clean the differential mounting bolt holes and inspect threads for damage.
12. 12

    Install replacement differential
    Apply a thin bead of Honda Bond HT or equivalent RTV sealant to the differential mating surface if gasket is not used. Carefully lift the replacement differential assembly into position and align it with the transmission case opening. Ensure proper engagement with internal components. Install new mounting bolt seals on all mounting bolts.
13. 13

    Torque differential mounting bolts
    Install all four differential mounting bolts with new sealing washers. Tighten the bolts in a criss-cross pattern to ensure even seating. Torque all mounting bolts to specification using a torque wrench.
    Torque spec

    Mounting Bolts26 Nm (19 lb-ft)
14. 14

    Install differential cover
    Apply new gasket or thin bead of RTV sealant to differential cover mating surface. Position cover and install all cover screws. Tighten screws in a criss-cross pattern to ensure even seating, then torque to specification.
    Torque spec

    Cover Screws10 Nm (8 lb-ft)
15. 15

    Reinstall axle assemblies
    Clean the axle splines and apply a light coat of fresh transmission fluid. Insert each axle into its respective hub, ensuring full engagement with the hub bearing. Align the inner CV joints with the differential or intermediate shaft flanges. Install all CV joint bolts and torque to specification in a star pattern.
    Torque spec

    CV Bolts58 Nm (43 lb-ft)
16. 16

    Install new axle nuts
    Install new (never reused) 32mm axle nuts on both front hubs. Tighten the nuts hand-tight at this stage. Final torquing will be performed with the vehicle on the ground.
17. 17

    Refill transmission fluid
    Install new drain plug washer on drain plug and reinstall drain plug hand-tight, then torque to specification per service manual. Locate the transmission fill plug on the side of the transmission case. Using a transmission fluid pump, refill the transmission with Honda DW-1 ATF through the fill hole until fluid begins to drip from the fill hole. Install fill plug.
18. 18

    Reinstall wheels and lower vehicle
    Reinstall both front wheels and hand-tighten lug nuts in a star pattern. Reinstall all undercovrs and splash shields. Carefully lower the vehicle to the ground. Remove jack stands.
19. 19

    Final torquing
    With the vehicle on the ground and parking brake applied, torque both front axle nuts to specification using a torque wrench and 32mm socket. Torque wheel lug nuts to specification in a star pattern.
    Torque spec

    Axle Nut232 Nm (171 lb-ft)

    Wheel Lug Nuts129 Nm (95 lb-ft)

Reassembly

1. Ensure all mounting bolts are torqued to proper specification
2. Verify axle nuts are torqued with vehicle on ground and parking brake applied
3. Double-check that new axle nuts were used (not old nuts)
4. Confirm transmission fluid level is correct and no leaks are present

Verification

• Start the engine and allow it to reach operating temperature while checking for fluid leaks around the differential cover and mounting points
• With the engine running, shift through all gear positions (P-R-N-D) several times to circulate fluid
• Check transmission fluid level using the fill plug method - fluid should drip slowly from fill hole when at operating temperature
• Test drive the vehicle at low speeds in a safe area, listening for any abnormal noises from the differential or axles
• Perform figure-eight turns in both directions to load the differential and verify smooth operation
• After test drive, recheck all mounting bolts, axle nuts, and fluid level
• Inspect for any fluid leaks after 50-100 miles of driving

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