This procedure covers removal and replacement of the flexplate on a 2015-2020 Ford F-150 with 3.5L EcoBoost engine and automatic transmission, requiring transmission removal.

Warnings

Tools required

Parts

• Flexplate × 1 — Use OEM Ford flexplate for 3.5L EcoBoost
• Flexplate bolts × 8 — Use new OEM bolts, torque-to-yield design
• Transmission pan gasket × 1 — Use OEM specification
• Transmission fluid filter × 1 — Use OEM specification

Fluids

• Motorcraft MERCON LV ATF — 11 qt

Preparation

1. Park vehicle on level surface and engage parking brake
2. Disconnect negative battery cable
3. Raise vehicle and secure on jack stands at all four corners at manufacturer-specified lift points
4. Remove engine splash shields and undertray
5. Mark driveshaft-to-differential flange orientation for reassembly alignment
6. Place drain pan under transmission and drain transmission fluid by removing pan bolts gradually
7. Allow engine to cool completely if recently operated

Procedure

1. 1

   Remove driveshaft
   Remove the four driveshaft-to-rear differential flange bolts. Support driveshaft and remove transmission yoke bolts. Slide driveshaft rearward to disengage from transmission and lower carefully. Cap transmission output shaft to prevent fluid loss and contamination.
2. 2

   Disconnect transmission electrical connections and cooler lines
   Disconnect transmission wiring harness connector at transmission case. Disconnect transmission cooler lines at transmission using appropriate line disconnect tool. Cap or plug lines to prevent contamination. Disconnect transmission shift cable from transmission lever and bracket.
3. 3

   Support engine and transmission
   Install engine support bar across engine bay to support engine weight, or attach engine hoist to lifting eyes. Position transmission jack under transmission pan with safety chain. Apply slight upward pressure to transmission to relieve weight from mounts.
   ⚠️Engine and transmission must be properly supported before removing any mounts. Failure to do so can result in component damage or serious injury.
4. 4

   Remove transmission crossmember
   Remove transmission mount-to-crossmember bolts. Remove crossmember-to-frame bolts and remove crossmember from vehicle. Support transmission weight entirely on transmission jack.
   Torque spec

   Mounting Bolts31 Nm (23 lb-ft)
5. 5

   Remove starter motor
   Disconnect starter electrical connections including battery cable and solenoid wire. Remove starter motor mounting bolts and carefully remove starter from bellhousing. Set aside in safe location.
6. 6

   Access torque converter bolts
   Through starter opening, rotate crankshaft using a socket on crankshaft pulley bolt to access each torque converter bolt. Mark torque converter-to-flexplate orientation with paint pen. Remove all torque converter-to-flexplate bolts and push torque converter back into transmission bellhousing.
   ⚠Ensure torque converter is fully seated in transmission after removal. It should be recessed approximately 1/2 inch from bellhousing face.
   Torque spec

   Torque Converter Bolts50 Nm (37 lb-ft)
7. 7

   Remove transmission-to-engine bolts
   Remove all transmission-to-engine bellhousing bolts. Note different bolt lengths and locations for reassembly. Remove any ground straps or brackets attached to bellhousing bolts.
   Torque spec

   Transmission-to-Engine Bolts55 Nm (41 lb-ft)
8. 8

   Separate and remove transmission
   Carefully slide transmission rearward on transmission jack, ensuring torque converter remains fully seated in transmission and does not fall out. Continue moving transmission rearward until input shaft clears engine. Slowly lower transmission and remove from under vehicle. Install torque converter holding strap or wire to prevent it from falling out during handling.
   ⚠️Transmission weight shifts as it is pulled away from engine. Maintain positive control and have assistance available.
9. 9

   Inspect and remove flexplate
   Inspect flexplate for cracks, especially around bolt holes and ring gear. Check ring gear teeth for damage or wear. Use flexplate holding tool or have assistant hold crankshaft from rotating using large pry bar against ring gear. Mark flexplate-to-crankshaft orientation if reusing. Remove all flexplate bolts in a crisscross pattern. Remove flexplate from crankshaft.
   ⚠Do not pry on flexplate or use impact tools for removal. Flexplate is brittle and can crack easily.
10. 10

    Clean and inspect crankshaft flange
    Clean crankshaft flange thoroughly with brake cleaner. Inspect crankshaft flange for cracks, damage, or excessive runout. Check crankshaft rear main seal for leaks; replace if leaking. Inspect pilot bearing/bushing condition if equipped. Clean all old thread locker from crankshaft bolt holes using appropriate tap or thread chaser.
    ℹ️This is the ideal time to replace rear main seal if any seepage is present, as transmission is already removed.
11. 11

    Install new flexplate
    Apply medium-strength thread locker to new flexplate bolt threads. Position new flexplate onto crankshaft, aligning bolt holes and ensuring correct orientation (offset bolt holes only allow one position). Install all flexplate bolts finger-tight. Using flexplate holding tool to prevent rotation, torque flexplate bolts in a star pattern to specification in three progressive stages: first to 30 Nm, then to 60 Nm, finally to 85 Nm. Verify proper tightening sequence in factory service manual.
    ⚠Incorrect torque sequence can warp flexplate or damage crankshaft. Follow star pattern and progressive torque stages.
    Torque spec

    Flexplate Bolts85 Nm (63 lb-ft)
12. 12

    Prepare transmission for installation
    Replace transmission filter and pan gasket. Install new filter and pan with new gasket. Ensure torque converter is fully seated in transmission pump (should click into place and be recessed from bellhousing face). Verify torque converter rotates freely. Apply small amount of high-temp grease to torque converter pilot.
    Torque spec

    Gasket Bolts23 Nm (17 lb-ft)
13. 13

    Install transmission
    Raise transmission into position on transmission jack. Align transmission with engine, ensuring torque converter hub engages with flexplate pilot. Carefully slide transmission forward, rotating torque converter slightly if needed to align bolt holes. Continue until transmission bellhousing contacts engine block evenly. Do not force or use bolts to draw transmission to engine.
    ⚠If transmission does not slide easily to engine, stop and verify torque converter is properly seated and aligned. Never use bolts to pull transmission to engine.
14. 14

    Install transmission-to-engine bolts and torque converter bolts
    Install all transmission-to-engine bellhousing bolts and torque to specification in a crisscross pattern. Reinstall any ground straps or brackets. Rotate crankshaft to access torque converter bolt holes through starter opening. Align marks made during removal. Install torque converter bolts and torque to specification, following proper sequence per service manual. Verify all bolts are tight.
    Torque spec

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

    Torque Converter Bolts50 Nm (37 lb-ft)
15. 15

    Reinstall remaining components
    Install starter motor and torque mounting bolts. Reconnect starter electrical connections. Install transmission crossmember and torque all mounting bolts to specification. Remove engine support and transmission jack. Reconnect transmission cooler lines and electrical connections. Reconnect shift cable to transmission. Install driveshaft, aligning marks made during removal. Torque driveshaft bolts to specification. Install transmission pan drain plug if equipped. Fill transmission with Motorcraft MERCON LV ATF to proper level. Reinstall splash shields and undertray.
    Torque spec

    Mounting Bolts31 Nm (23 lb-ft)

Reassembly

1. Torque all fasteners to specification using proper sequence where applicable
2. Ensure all electrical connections are fully seated and secured
3. Verify transmission cooler lines are properly connected and secured
4. Double-check that all bolts are installed and torqued before lowering vehicle

Verification

• With engine off, verify transmission fluid level is correct using dipstick (if equipped) or fill plug
• Start engine and verify no fluid leaks from transmission pan, cooler lines, or rear main seal
• Shift through all transmission gears with foot on brake, verifying smooth engagement
• Test drive vehicle and verify normal transmission operation with no abnormal noises, vibrations, or slippage
• Listen for starter engagement - should be smooth with no grinding noise indicating proper flexplate-to-ring gear alignment
• Recheck transmission fluid level with engine at operating temperature and adjust as needed
• Inspect underneath vehicle for any fluid leaks after test drive

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