Transmission Rebuild - Automatic

Complete disassembly, inspection, rebuild and reinstallation of the CVT automatic transmission for the 2016-2021 Honda Civic 1.5L Turbo, including removal from vehicle, internal component replacement, and system refill.

Warnings

Tools required

Parts

• CVT rebuild kit with bearings and seals × 1 — Use Honda OEM CVT rebuild kit
• CVT steel chain or belt assembly × 1 — Inspect and replace if worn - Honda OEM
• Drive pulley assembly × 1 — Replace if damaged - Honda OEM
• Driven pulley assembly × 1 — Replace if damaged - Honda OEM
• Valve body gasket set × 1 — Honda OEM valve body gasket kit
• Transmission case gasket × 1 — Honda OEM case gasket
• Torque converter seal × 1 — Honda OEM front seal
• Output shaft seal × 2 — Honda OEM output seal
• Transmission drain plug crush washer × 2 — 94109-24000 or equivalent
• Transmission filter × 1 — Honda OEM CVT filter
• Solenoid set × 1 — Inspect and replace if faulty - Honda OEM
• ATF cooler line O-rings × 1 — Honda OEM cooler line seals

Fluids

• Honda DW-1 ATF — 8 qt

Preparation

1. Park vehicle on level ground and engage parking brake
2. Disconnect negative battery cable and wait 3 minutes for SRS system discharge
3. Raise vehicle on lift or support securely on jack stands at all four corners
4. Remove front wheels and engine splash shields
5. Drain transmission fluid completely using drain plug, collect in approved container for disposal
6. Remove front subframe bracing if equipped
7. Disconnect transmission cooler lines and plug openings to prevent contamination
8. Install engine support fixture across engine bay to support engine weight
9. Prepare clean workspace for transmission disassembly with parts washing capability
10. Have Honda factory service manual available for CVT-specific clearance specifications and diagrams

Procedure

1. 1

   Remove transmission from vehicle
   Disconnect all electrical connectors from transmission including shift solenoids, speed sensors, and range switch. Remove starter motor and upper transmission mounting bolts accessible from engine bay. Disconnect shift cable from transmission lever. Remove front axle shafts from transmission by removing axle nuts and separating ball joints, then carefully prying axles from differential using appropriate tools. Support transmission with transmission jack. Remove remaining transmission mounting bolts and lower engine mounts. Carefully separate transmission from engine, ensuring torque converter remains with transmission. Lower transmission from vehicle on transmission jack.
2. 2

   External inspection and cleaning
   Clean exterior of transmission thoroughly with brake cleaner. Inspect transmission case for cracks, damage, or porosity. Check all mounting bosses for cracks or stripped threads. Inspect cooler line fittings for damage. Mark torque converter position relative to transmission case before removal. Remove torque converter and inspect for damage, scoring, or discoloration indicating overheating.
3. 3

   Remove valve body and filter
   Position transmission with pan facing up. Remove transmission pan bolts in criss-cross pattern. Carefully remove pan and gasket material. Remove transmission filter. Disconnect all electrical connectors from valve body. Remove valve body mounting bolts carefully, noting different bolt lengths and positions. Carefully lower valve body assembly, keeping it level to prevent check balls from falling out. Place valve body on clean surface and cover with lint-free cloth.
   Torque spec

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

   Split transmission case
   Remove all case cover bolts noting their positions as lengths vary. Use plastic-tipped hammer to gently tap case at designated pry points to separate halves. Do not pry between sealing surfaces. Carefully lift case cover straight up to avoid damaging components. Inspect case interior for metal debris, damaged bearing races, or scoring. Document condition with photos.
   Torque spec

   Cover Screws10 Nm (8 lb-ft)
5. 5

   Remove and inspect CVT pulley assemblies
   Install CVT pulley holding tool on drive pulley. Remove drive pulley retaining hardware per service manual procedures while maintaining pulley under compression with holding tool. Carefully release spring tension using proper tool. Remove drive pulley assembly and place on clean surface. Repeat process for driven pulley. Remove CVT chain/belt assembly, marking direction of rotation and orientation. Inspect chain/belt for wear, cracks, or damage. Measure chain/belt for stretch against service limits. Inspect pulley faces for scoring, wear patterns, or discoloration.
   ⚠️Pulleys contain high-tension springs. Failure to use proper holding tools can result in violent release causing serious injury.
6. 6

   Remove shafts and gear assemblies
   Remove snap rings securing shafts in place. Use dial indicator to measure endplay of all shafts before removal, recording measurements. Carefully remove input shaft assembly. Remove output shaft assembly. Remove differential assembly with care to avoid damaging bearings. Remove all gears, thrust washers, and bearings, keeping components organized by shaft in clean containers. Inspect all gear teeth for wear, chips, or discoloration. Check all bearing surfaces for scoring or roughness.
7. 7

   Disassemble and inspect valve body
   Work on extremely clean surface. Remove valve body cover plate bolts and carefully lift cover. Photograph valve body layout before disassembly for reassembly reference. Remove each valve, spring, and check ball systematically, organizing in compartmented tray. Inspect all valve bores for scoring or wear. Check valves for freedom of movement and scoring. Measure spring free length and compare to specifications. Clean all components in approved transmission parts cleaner. Inspect separator plate for damage. Verify all orifices are clear.
   ⚠Valve body contains numerous small check balls and springs. Work deliberately and maintain organization to ensure correct reassembly.
8. 8

   Clean and inspect all components
   Thoroughly clean all internal components in parts washer using approved transmission cleaner. Inspect all bearing races in case for pitting, scoring, or discoloration. Check all thrust bearing surfaces for wear. Inspect oil pump assembly for scoring or wear on gear faces. Measure all shaft diameters at bearing surfaces and compare to specifications. Check all snap ring grooves for damage. Inspect parking pawl mechanism for wear. Clean case halves meticulously, ensuring all oil passages are clear by blowing with compressed air.
9. 9

   Replace bearings and seals
   Use hydraulic press with appropriate drivers to remove all bearings from case. Press in new bearings ensuring they are square and seated to proper depth. Install new case seals using seal drivers, ensuring seals are not cocked or damaged during installation. Replace all O-rings throughout transmission. Install new torque converter seal in transmission case. Replace output shaft seals on both sides. Lubricate all seals with Honda DW-1 ATF before installation.
10. 10

    Reassemble valve body
    Install all valves, springs, and check balls in valve body per factory service manual diagrams and photos taken during disassembly. Verify each valve moves freely in its bore. Install new separator plate gaskets. Carefully position separator plate ensuring all passages align correctly. Install valve body cover with new gasket. Torque valve body cover bolts to specification in criss-cross pattern. Install all solenoids with new O-rings, ensuring proper seating.
    Torque spec

    Sensor Bolts10 Nm (8 lb-ft)
11. 11

    Reassemble internal components
    Lubricate all components liberally with Honda DW-1 ATF during assembly. Install differential assembly with proper thrust washers and shims. Install output shaft assembly with all gears, thrust washers, and bearings in correct order per service manual. Install input shaft assembly. Install all snap rings ensuring they are fully seated in grooves. Measure endplay of all shafts using dial indicator and compare to specifications recorded during disassembly. Adjust with selective thrust washers or shims as needed to achieve proper endplay.
12. 12

    Install CVT pulley assemblies
    Install new or inspected CVT chain/belt in correct orientation as marked during removal. Position driven pulley assembly and secure with proper holding tool. Install and torque retaining hardware per service manual while maintaining spring compression. Position drive pulley assembly and secure similarly. Verify pulleys rotate smoothly and chain/belt tracks correctly on pulley faces. Check that chain/belt has proper tension and does not bind.
13. 13

    Reassemble transmission case
    Apply thin bead of Honda Bond sealant or install new case gasket per service manual specifications on case mating surface. Carefully position case cover over assembly, ensuring all components remain in position. Install all case bolts finger-tight, then torque in criss-cross pattern to specification. Verify case halves are fully seated with no gaps.
    Torque spec

    Cover Screws10 Nm (8 lb-ft)
14. 14

    Install valve body and pan
    Position new valve body gasket on case. Carefully install valve body assembly ensuring it seats properly and all passages align. Install valve body mounting bolts and torque to specification. Connect all electrical connectors to solenoids and sensors. Install new transmission filter. Clean pan thoroughly and install with new gasket. Torque pan bolts in criss-cross pattern to specification. Install drain plug with new crush washer.
    Torque spec

    Pan Bolts15 Nm (11 lb-ft)

    Transmission Drain Plug30 Nm (22 lb-ft)
15. 15

    Reinstall transmission in vehicle
    Install torque converter in transmission ensuring it is fully seated with multiple engagement clicks. Carefully raise transmission into position using transmission jack. Align transmission with engine and carefully push together, ensuring torque converter hub engages with pump. Install all transmission mounting bolts and torque to specifications - use 58 Nm for main mounting bolts and 26 Nm for smaller mounting bolts. Reconnect shift cable and adjust per service manual. Install axle shafts into transmission with new circlips. Reconnect all electrical connectors. Install starter motor. Reconnect transmission cooler lines with new O-rings. Install engine splash shields and wheels. Remove engine support fixture. Fill transmission with Honda DW-1 ATF through fill port using fluid pump until fluid begins to drip from fill hole with engine running at operating temperature. Reconnect battery negative cable.
    Torque spec

    Mounting Bolts58 Nm (43 lb-ft)

    Flywheel Bolts95 Nm (70 lb-ft)

Reassembly

1. All snap rings must be fully seated in their grooves with no gaps
2. Endplay specifications are critical for CVT longevity - verify all clearances match factory specifications
3. Ensure CVT chain/belt is installed in correct orientation and tracks properly on pulley faces
4. All internal components must be liberally lubricated with Honda DW-1 ATF during assembly
5. Torque all fasteners in specified patterns and sequences to ensure even clamping force
6. Verify all electrical connectors are fully seated and latched

Verification

• Start engine and verify no transmission fluid leaks from case, pan, cooler lines, or seals
• With engine at idle and parking brake applied, shift through all gear ranges verifying smooth engagement
• Check that shift indicator matches actual transmission position in all ranges
• Road test vehicle verifying smooth acceleration with no slipping, shuddering, or abnormal noises
• Verify transmission shifts smoothly through entire operating range under various load conditions
• Check transmission fluid level with engine at operating temperature and verify proper level at fill hole
• Scan for diagnostic trouble codes and verify no transmission-related codes are present
• Monitor transmission temperature during test drive to ensure proper cooling system operation
• Re-check fluid level after test drive and top off if necessary
• Inspect for leaks again after test drive with transmission at operating temperature

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