Rear Main Seal

This procedure involves removing the transmission to replace the rear main crankshaft seal, which prevents engine oil from leaking at the rear of the crankshaft.

Warnings

Tools required

Parts

• Rear main crankshaft seal × 1 — Use OEM Honda part
• Transmission fluid × 1 — Honda DW-1 ATF (automatic) or Honda MTF (manual)
• Engine oil and filter × 1 — 0W-20 and Honda oil filter
• Oil drain plug crush washer × 1 — Use OEM specification
• Rear main seal housing gasket (if equipped) × 1 — Use OEM Honda part

Fluids

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

Preparation

1. Park vehicle on level ground and apply parking brake
2. Disconnect negative battery cable and secure away from terminal
3. Raise vehicle and support securely on jack stands at all four corners
4. Remove engine under cover and splash shields
5. Drain engine oil and remove oil filter
6. Drain transmission fluid from drain plug
7. Remove front wheels if additional working room is needed
8. Install engine support bar across engine bay or attach hoist to engine lifting points

Procedure

1. 1

   Disconnect driveshafts and remove exhaust components
   Remove both front driveshaft axle nuts (32mm). Separate driveshafts from transmission by prying at inner CV joints with a pry bar; be careful not to damage seals. Support driveshafts with wire. Disconnect exhaust downpipe from turbo and catalytic converter. Remove exhaust hangers and lower exhaust system enough to provide clearance for transmission removal.
2. 2

   Disconnect electrical and shift linkages
   Disconnect all electrical connectors from transmission including: shift solenoid harness, vehicle speed sensor, reverse light switch, and transmission range switch. Remove shift cable from transmission by removing cable bracket bolts. On CVT models, disconnect the harness connector from the transmission control module mounted on the transmission. Label all connections for reassembly.
3. 3

   Remove transmission cooler lines and ground cables
   Disconnect transmission cooler lines from transmission. Have a drain pan ready as residual fluid will drain. Remove the ground cable bolts from the transmission case. Remove the starter motor by disconnecting electrical connections and removing mounting bolts. Support starter and set aside.
4. 4

   Support transmission and remove mounts
   Position transmission jack or suitable support under transmission oil pan with a block of wood to distribute load. Remove the rear transmission mount and crossmember by removing mounting bolts. Remove both side transmission mount bolts. Ensure engine is properly supported by the engine support bar before proceeding.
   Torque spec

   Mounting Bolts45 Nm (33 lb-ft)
5. 5

   Remove transmission bell housing bolts
   Remove all transmission-to-engine bolts. There are typically 4-5 bolts around the bell housing perimeter. Note the location of different length bolts for reinstallation. Remove the lower torque converter/flywheel access cover if not already removed.
   Torque spec

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

   Cover Bolts15 Nm (11 lb-ft)
6. 6

   Remove torque converter bolts (automatic only)
   For automatic/CVT transmissions, rotate the crankshaft using a breaker bar on the crankshaft bolt to access each flexplate-to-torque converter bolt through the access opening. Remove all bolts (typically 3-4 bolts). Mark the relationship between flexplate and torque converter for proper reassembly alignment.
   ⚠Support torque converter when separating transmission to prevent it from falling out.
   Torque spec

   Flexplate Bolts85 Nm (63 lb-ft)
7. 7

   Separate and remove transmission
   Carefully pull transmission straight back away from engine, ensuring torque converter stays with transmission. Lower transmission using transmission jack. On CVT models, be especially careful as these transmissions are fragile. Once clear of vehicle, set transmission on a secure workbench or transmission stand.
8. 8

   Remove flexplate or flywheel
   Lock the flexplate/flywheel using a flywheel holding tool or large screwdriver wedged in ring gear. Remove all flexplate bolts (automatic) or flywheel bolts (manual) in a star pattern. Note the orientation and any alignment dowels. Remove flexplate/flywheel from crankshaft.
   ℹ️Flywheel bolts on manual transmission are often torque-to-yield (TTY) and must be replaced with new bolts.
   Torque spec

   Flexplate Bolts85 Nm (63 lb-ft)
9. 9

   Remove old rear main seal
   Inspect the rear main seal housing for bolts. If the housing is bolted on, remove housing bolts and carefully pry housing away from engine block. Clean all gasket material from mating surfaces. If seal is pressed directly into block, use a seal puller or carefully pry out the old seal using a flat blade screwdriver. Be extremely careful not to damage the crankshaft sealing surface or the seal bore in the block.
   ⚠Do not score or scratch the crankshaft surface as this will cause the new seal to leak.
   Torque spec

   Rear Main Seal Housing12 Nm (9 lb-ft)
10. 10

    Clean and inspect sealing surfaces
    Thoroughly clean the crankshaft flange and seal bore using brake cleaner and lint-free rags. Inspect crankshaft for grooves, scratches, or wear in the seal contact area. Minor imperfections can be smoothed with fine emery cloth. Check for proper crankshaft endplay. Clean the rear main seal housing (if separate) and inspect for cracks or damage.
11. 11

    Install new rear main seal
    Lightly coat the outer diameter of the new seal with engine oil. Apply a small amount of engine oil to the seal lip. Using a rear main seal installation tool or appropriately sized large socket, carefully drive the seal into the bore evenly. The seal must go in straight to avoid damage. Drive until flush with the housing or block surface. If using a separate housing, install new gasket and install housing with seal already pressed in, torquing bolts to specification in a criss-cross pattern.
    ⚠Seal must be installed evenly and squarely. A cocked seal will leak immediately.
    Torque spec

    Rear Main Seal Housing12 Nm (9 lb-ft)
12. 12

    Reinstall flexplate or flywheel
    Clean crankshaft flange and flexplate/flywheel mating surfaces. Align flexplate/flywheel onto crankshaft ensuring any alignment dowels are properly seated. Install flexplate or flywheel bolts (use new bolts if TTY type). Lock the flexplate/flywheel and torque bolts in a star pattern to specification. For flywheel, follow TTY tightening sequence if applicable.
    ℹ️Ensure correct flexplate orientation. Torque converter mounting surface must face transmission.
    Torque spec

    Flexplate Bolts85 Nm (63 lb-ft)
13. 13

    Reinstall transmission
    Raise transmission into position using transmission jack. For automatic, ensure torque converter is fully seated in transmission pump (should have two distinct clicks when pushed in). Align transmission with engine and carefully slide into place. Install all transmission-to-engine bolts and torque to specification. Install starter motor and torque mounting bolts.
    ⚠Verify torque converter is fully engaged before mating transmission to engine. Improper seating will damage transmission pump.
    Torque spec

    Transmission-to-Engine Bolts55 Nm (41 lb-ft)
14. 14

    Install torque converter bolts and reconnect components
    Rotate crankshaft to align torque converter with flexplate using alignment marks made during disassembly. Install torque converter bolts and torque to specification while rotating crankshaft to access each bolt. Install torque converter cover. Reinstall transmission mounts and crossmember, torquing all mounting bolts to specification. Remove transmission jack and engine support.
    Torque spec

    Flexplate Bolts85 Nm (63 lb-ft)

    Cover Bolts15 Nm (11 lb-ft)

    Mounting Bolts45 Nm (33 lb-ft)
15. 15

    Reconnect all lines and driveshafts
    Reconnect transmission cooler lines and ensure fittings are secure. Reconnect all electrical connectors to transmission components. Install shift cable and adjust if necessary. Reconnect exhaust system and torque all fasteners. Install driveshafts into transmission (new circlips recommended) and install axle nuts finger-tight. Install ground cables.
16. 16

    Refill fluids and final assembly
    Install new oil drain plug crush washer and torque drain plug to specification. Install new oil filter and fill engine with correct amount of 0W-20 oil. Fill transmission with Honda DW-1 ATF through fill plug or dipstick tube (depending on model). Reinstall splash shields and under covers. Lower vehicle and torque axle nuts to specification. Reconnect battery.
    ℹ️CVT transmission fluid level must be checked at specific temperature (95-113°F) with engine running.
    Torque spec

    Oil Drain Plug35 Nm (26 lb-ft)

Reassembly

1. Follow steps in reverse order from disassembly
2. Always use new crush washers, gaskets, and TTY bolts where applicable
3. Torque all fasteners to specification in the proper sequence
4. Ensure all electrical connections are properly seated and secured
5. Double-check that torque converter is fully engaged before bolting transmission to engine

Verification

• Check engine oil level and top off if necessary using dipstick
• Check transmission fluid level using proper procedure (engine running at operating temperature for CVT)
• Start engine and check for oil leaks at rear main seal area
• Allow engine to reach operating temperature and recheck for leaks
• Test drive vehicle and verify proper transmission operation, checking for any fluid leaks after test drive
• Verify no warning lights on dashboard and all transmission functions work correctly
• Recheck all fluid levels after test drive and top off if needed

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