This procedure involves removing the transmission to access and replace the rear main crankshaft seal on a 2015 Kia Forte with 1.8L I4 engine.

Warnings

Tools required

Parts

• Rear main crankshaft seal × 1 — Use OEM specification
• Rear main seal housing gasket × 1 — Use OEM specification
• Engine oil drain plug crush washer × 1 — Use OEM specification
• Engine oil filter × 1 — Use OEM specification
• Transmission fluid (if drained) × 1 — SP-IV-M ATF

Fluids

• Kia Genuine 5W-20 — 4.5 qt
• Kia SP-IV-M ATF — 10 qt

Preparation

1. Disconnect negative battery cable and secure away from battery post
2. Raise vehicle on lift or secure on jack stands at manufacturer-specified lift points
3. Remove engine splash shield and lower covers
4. Drain engine oil completely and remove oil filter
5. Install engine support bar across engine bay or attach engine hoist to lifting eyes
6. Remove air intake assembly for workspace access

Procedure

1. 1

   Disconnect transmission electrical connections and cooler lines
   Disconnect all electrical connectors from transmission including speed sensors, range switch, and solenoid connectors. Label each connector for reassembly. Disconnect transmission cooler lines at transmission using line disconnect tool, catch residual fluid in drain pan. Cap open lines to prevent contamination.
2. 2

   Remove exhaust system components
   Disconnect front exhaust pipe from catalytic converter and exhaust manifold. Remove any exhaust hangers or brackets that will interfere with transmission removal. Lower exhaust system and secure out of work area.
3. 3

   Remove transmission mounting components
   Remove front and rear transmission mount bolts. Remove transmission cross member bolts and carefully lower cross member. Ensure engine support bar is securely holding engine weight before removing mounts completely.
   Torque spec

   Mounting Bolts26 Nm (19 lb-ft)
4. 4

   Disconnect shift linkage and remaining brackets
   Disconnect shift cable from transmission lever and remove cable bracket. Remove any ground straps, wiring harness brackets, or remaining components attached to transmission bell housing.
5. 5

   Remove torque converter access cover and flexplate bolts
   Remove torque converter access cover from bottom of bell housing. Rotate crankshaft using harmonic balancer bolt to access each flexplate-to-torque converter bolt through access opening. Use flexplate holder tool or have assistant hold crankshaft while removing bolts. Remove all flexplate bolts and push torque converter back into transmission to prevent falling during removal.
   ⚠Mark flexplate-to-torque converter position before removal for proper balance during reassembly.
   Torque spec

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

   Remove transmission-to-engine bolts
   Support transmission securely with transmission jack positioned at transmission pan. Remove all transmission-to-engine bolts including starter motor bolts. Verify all bolts are removed before attempting to separate transmission.
   Torque spec

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

   Separate and lower transmission
   Carefully pull transmission straight back from engine ensuring torque converter remains in transmission. Once transmission is clear of alignment dowels, carefully lower transmission jack and remove transmission from under vehicle. Do not allow transmission to hang on input shaft.
   ⚠️Ensure torque converter is fully seated in transmission pump and secure before lowering. A falling torque converter can cause serious injury.
8. 8

   Remove flexplate from crankshaft
   Hold flexplate with flexplate holder tool or lock crankshaft rotation. Remove all flexplate-to-crankshaft bolts in reverse star pattern sequence. Remove flexplate from crankshaft and set aside. Inspect flexplate for cracks or damaged ring gear.
   Torque spec

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

   Remove rear main seal housing
   Remove all rear main seal housing bolts. Carefully pry housing from engine block using pry points if provided, or gently tap with plastic mallet. Remove housing and old gasket material. Clean all mating surfaces thoroughly with gasket scraper, ensuring no debris falls into crankcase.
   ⚠Do not damage aluminum housing or engine block sealing surfaces. Deep scratches will cause oil leaks.
   Torque spec

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

    Remove and replace rear main seal
    Using seal puller or carefully prying, remove old rear main seal from housing. Clean housing bore thoroughly. Lubricate new seal lip with clean engine oil. Using appropriately sized seal driver, install new seal squarely into housing bore until fully seated and flush with housing surface. Verify seal is not cocked or damaged.
11. 11

    Install rear main seal housing
    Install new housing gasket on engine block (or apply thin bead of RTV if gasket not used). Position rear main seal housing on crankshaft and align with engine block. Hand-start all housing bolts, then torque in cross pattern sequence starting from center bolts working outward.
    Torque spec

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

    Reinstall flexplate
    Clean flexplate bolt holes and threads. Position flexplate on crankshaft with previously marked orientation. Apply threadlocker to flexplate bolts if specified by manufacturer. Install bolts hand-tight, then torque in star pattern sequence. If bolts are TTY (torque-to-yield), replace with new bolts and follow proper tightening procedure.
    ℹ️Flywheel/flexplate bolts are critical fasteners. Follow exact torque specifications and star pattern sequence.
    Torque spec

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

    Reinstall transmission
    Verify torque converter is fully seated in transmission (measure depth if specification available). Raise transmission into position with transmission jack. Align transmission with engine dowel pins and carefully slide transmission forward onto crankshaft. Install and hand-start all transmission-to-engine bolts before torquing any bolts. Torque all bolts to specification.
    Torque spec

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

    Install torque converter to flexplate
    Rotate crankshaft to align torque converter bolt holes with flexplate holes. Pull torque converter forward if necessary to engage flexplate. Install torque converter bolts through access cover opening, rotating crankshaft to access each bolt hole. Torque all bolts to specification. Install access cover.
    Torque spec

    Flexplate Bolts85 Nm (63 lb-ft)

    Cover Bolts15 Nm (11 lb-ft)
15. 15

    Reinstall remaining components and fill fluids
    Reinstall transmission mounts and cross member, torque to specification. Reconnect all electrical connectors, shift linkage, and transmission cooler lines. Reinstall exhaust components. Install new oil drain plug crush washer and torque drain plug. Install new oil filter. Fill engine with 4.5 quarts Kia Genuine 5W-20 oil. Check and fill transmission with SP-IV-M ATF to proper level. Reinstall all covers and shields. Reconnect battery.
    Torque spec

    Mounting Bolts26 Nm (19 lb-ft)

    Oil Drain Plug35 Nm (26 lb-ft)

Reassembly

1. Torque all fasteners in specified sequences and to exact specifications
2. Ensure all electrical connectors are fully seated with positive engagement
3. Verify transmission is filled to proper level with correct ATF specification
4. Double-check that all ground straps and wiring harness brackets are reinstalled

Verification

• Start engine and verify no oil leaks from rear main seal housing area
• Check transmission fluid level with engine at operating temperature in Park
• Test drive vehicle through all gear ranges and verify proper transmission operation
• Recheck oil level after test drive and inspect for leaks at rear main seal area
• Monitor for leaks over first 100 miles of operation

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