This procedure covers the removal and replacement of the flexplate on a 2016-2021 Honda Civic with the 1.5L turbocharged engine and automatic transmission, requiring transmission removal.

Warnings

Tools required

Parts

• Flexplate × 1 — Use OEM Honda specification
• Flexplate bolts × 8 — OEM Honda, replace-on-install
• Transmission gasket/seal kit × 1 — Use OEM specification
• Engine oil drain plug crush washer × 1 — 94109-14000
• Transmission drain plug sealing washer × 1 — 90471-PX4-000

Fluids

• Honda DW-1 ATF — 8 qt
• Honda Genuine 0W-20 Engine Oil — 4 qt

Preparation

1. Park vehicle on level surface and engage parking brake
2. Disconnect negative battery terminal and wait 3 minutes for airbag system to discharge
3. Remove engine cover by pulling upward on clips
4. Raise and securely support vehicle on jack stands or lift at proper lift points
5. Remove front wheels
6. Remove engine splash shield and undercovers
7. Drain engine oil and transmission fluid into appropriate containers
8. Install engine support fixture across engine bay to support engine weight

Procedure

1. 1

   Remove front subframe and driveshafts
   Remove both front driveshafts from transmission by removing axle nuts and lower ball joints. Separate driveshafts from transmission using appropriate puller or pry bar technique. Support driveshafts with wire to prevent CV joint damage. Remove front subframe mounting bolts and lower subframe assembly to provide access.
2. 2

   Disconnect transmission electrical and cooling connections
   Disconnect all transmission electrical connectors including shift solenoids, speed sensors, and range switch. Label each connector for reassembly reference. Disconnect transmission cooler lines and cap openings to prevent fluid loss and contamination. Remove ground cables from transmission.
   ⚠Residual ATF will drain from cooler lines. Have drain pan ready.
3. 3

   Remove starter motor and torque converter access
   Remove starter motor mounting bolts and carefully extract starter, disconnecting electrical connections. Remove lower torque converter inspection cover to access torque converter bolts. Rotate crankshaft using 19mm socket on crankshaft pulley bolt to access all torque converter bolts through opening.
   Torque spec

   Cover Bolts15 Nm (11 lb-ft)
4. 4

   Remove torque converter to flexplate bolts
   Mark position of torque converter to flexplate for reassembly reference. Remove all torque converter mounting bolts while preventing crankshaft rotation using flywheel holding tool or large screwdriver wedged between flexplate teeth and transmission housing. Keep torque converter pushed into transmission during removal to prevent dropping.
   ℹ️There are typically 4-6 torque converter bolts. Rotate crankshaft to access each bolt.
   Torque spec

   Torque Converter Bolts50 Nm (37 lb-ft)
5. 5

   Support and remove transmission
   Position transmission jack under transmission pan with proper adapter. Secure transmission to jack with safety strap. Remove transmission mounting bolts starting with upper bolts, then side mounting bolts. Verify engine is properly supported by engine support fixture. Remove rear transmission mount and crossmember.
   ⚠️Ensure transmission jack is centered and stable before removing final mounting bolts.
   Torque spec

   Mounting Bolts45 Nm (33 lb-ft)
6. 6

   Separate transmission from engine
   Remove all transmission-to-engine mounting bolts. Note bolt lengths and locations as they may vary. Carefully pull transmission straight back away from engine, ensuring torque converter remains fully seated in transmission. Lower transmission on jack and remove from under vehicle.
   ⚠Do not let transmission hang on input shaft. Pull straight back to avoid damaging components.
   Torque spec

   Transmission-to-Engine Bolts55 Nm (41 lb-ft)
7. 7

   Lock crankshaft and remove flexplate bolts
   Install flywheel holding tool or wedge large screwdriver between flexplate teeth and engine block to prevent crankshaft rotation. Using breaker bar and socket, loosen all flexplate mounting bolts in a cross pattern. Remove all bolts completely and keep for inspection.
   ⚠Flexplate bolts are high-strength and may be tight. Use proper technique to avoid bolt head damage.
8. 8

   Remove and inspect flexplate
   Carefully remove flexplate from crankshaft flange. Inspect crankshaft flange for damage, cracks, or worn dowel pins. Inspect torque converter pilot bearing in crankshaft center. Clean crankshaft flange thoroughly with brake cleaner and lint-free cloth. Inspect old flexplate for crack patterns to identify failure cause.
   ℹ️Common flexplate failure points are around bolt holes and at torque converter ring gear welds.
9. 9

   Install new flexplate
   Verify new flexplate matches old part exactly. Align flexplate onto crankshaft flange ensuring dowel pins engage properly. Install NEW flexplate bolts (do not reuse old bolts) with medium-strength thread locker applied to threads. Hand-thread all bolts first to ensure proper thread engagement.
   ⚠️Follow factory torque sequence exactly, typically in star pattern. Improper sequence can warp flexplate or crack crankshaft flange.
   Torque spec

   Flexplate Bolts85 Nm (63 lb-ft)
10. 10

    Torque flexplate bolts to specification
    Using torque wrench, tighten flexplate bolts to 85 Nm (63 lb-ft) in proper sequence per service manual. Use star/cross pattern, tightening in 2-3 stages (30%, 60%, 100% of final torque). Hold crankshaft with flywheel holding tool during torquing. Verify each bolt reaches proper torque.
    ⚠️Critical torque specification. Under-torquing causes bolt loosening and flexplate failure. Over-torquing can crack crankshaft flange.
    Torque spec

    Flexplate Bolts85 Nm (63 lb-ft)
11. 11

    Prepare transmission for reinstallation
    Clean transmission bell housing mating surface. Install new gasket or apply appropriate sealant per Honda specification. Verify torque converter is fully seated in transmission (should be recessed approximately 1/2 inch from bell housing face). Measure depth if unsure. Apply light coat of ATF to torque converter pilot.
    ⚠Torque converter must be fully seated in pump. If not seated, it will damage pump during installation.
    Torque spec

    Gasket Bolts19 Nm (14 lb-ft)
12. 12

    Reinstall transmission to engine
    Raise transmission on jack to engine. Align torque converter with flexplate, rotating torque converter as needed to align bolt holes with reference marks made during removal. Carefully guide transmission forward onto engine dowel pins. Install all transmission-to-engine bolts and torque in proper sequence to specification.
    ⚠Transmission should slide onto engine with light pressure. Do not force with bolts. Forcing indicates misalignment.
    Torque spec

    Transmission-to-Engine Bolts55 Nm (41 lb-ft)
13. 13

    Install torque converter bolts
    Rotate crankshaft to access torque converter bolt holes through inspection opening. Install torque converter bolts with thread locker and torque to 50 Nm (37 lb-ft) per service manual sequence. Hold crankshaft from rotating during torque. Verify all bolts are installed before proceeding.
    ℹ️Verify torque converter rotates freely by hand after bolt installation.
    Torque spec

    Torque Converter Bolts50 Nm (37 lb-ft)
14. 14

    Reinstall transmission mounts and components
    Install rear transmission mount and crossmember. Torque all mounting bolts to specification. Reinstall starter motor and torque mounting bolts. Install torque converter inspection cover and torque cover bolts to 15 Nm (11 lb-ft). Reconnect all transmission electrical connectors and ground cables in original locations.
    Torque spec

    Mounting Bolts45 Nm (33 lb-ft)

    Cover Bolts15 Nm (11 lb-ft)

    Sensor Bolts10 Nm (8 lb-ft)
15. 15

    Complete reassembly
    Reconnect transmission cooler lines and secure with proper clamps. Reinstall driveshafts into transmission and torque axle nuts to specification. Reinstall front subframe and torque all mounting bolts. Install splash shields and front wheels. Remove engine support fixture. Refill transmission with Honda DW-1 ATF to proper level. Refill engine oil. Reconnect battery negative terminal.

Reassembly

1. Follow steps in reverse order, ensuring all electrical connectors are properly seated and locked
2. Torque all fasteners to specification in proper sequence
3. Replace all crush washers and sealing washers during fluid refills
4. Double-check transmission fluid level after initial fill and after test drive

Verification

• Start engine and verify no warning lights illuminate on instrument cluster
• With engine at operating temperature, cycle through all gear positions and verify smooth engagement
• Check for fluid leaks around transmission pan, cooler lines, and bell housing
• Test drive vehicle through all gear ranges and verify normal operation with no vibration, noise, or harshness
• Recheck transmission fluid level with engine running at normal operating temperature in Park position
• Verify no abnormal noises from flexplate area during startup and acceleration
• Scan for diagnostic trouble codes to confirm no transmission-related faults are present

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