Flexplate

Replace the flexplate on a 1972 Ford F-100 with 302ci V8 and automatic transmission. Requires removing transmission to access flexplate between engine and torque converter.

Warnings

Tools required

Parts

• Flexplate (for 302 V8 with automatic transmission) × 1 — Use OEM specification or equivalent
• Flexplate-to-crankshaft bolts × 6 — Use OEM specification
• Flexplate-to-torque-converter bolts × 4 — Use OEM specification
• Transmission pan gasket × 1 — C4 or FMX transmission specific
• Rear main seal (if inspection shows leakage) × 1 — Use OEM specification
• Transmission output shaft seal (recommended replacement) × 1 — Use OEM specification

Fluids

• Type F ATF — 11 qt

Preparation

1. Park vehicle on level surface and engage parking brake.
2. Disconnect negative battery cable.
3. Raise vehicle and support securely on jack stands at frame rails.
4. Remove rear wheels if additional working clearance is needed under vehicle.
5. Allow engine and transmission to cool completely if recently operated.

Procedure

1. 1

   Drain transmission fluid
   Place drain pan under transmission pan. Remove all transmission pan bolts except two at the front corners. Loosen front bolts gradually to allow pan to tilt and drain fluid. Once drained, remove remaining bolts and lower pan. Remove and discard old gasket material from pan and transmission case.
2. 2

   Mark driveshaft orientation
   Use marking paint to mark the driveshaft yoke and rear axle pinion flange for proper reassembly alignment. Remove the 4 U-joint strap bolts at the rear axle. Slide driveshaft rearward to disengage from transmission output shaft and remove from vehicle.
3. 3

   Disconnect transmission linkages and cooler lines
   Disconnect shift linkage at transmission lever. Disconnect kickdown linkage if equipped. Place drain pan under cooler lines and disconnect both transmission cooler lines at the transmission fittings. Cap or plug lines and fittings to prevent contamination. Disconnect speedometer cable from transmission tailhousing.
4. 4

   Access torque converter bolts
   Working through the bellhousing inspection cover opening (if cover is present, remove it by removing the 2-3 bolts securing it), rotate the crankshaft using a socket on the front crankshaft bolt to bring each flexplate-to-torque-converter bolt into view. Mark the flexplate and torque converter with paint to maintain orientation. Remove all 4 flexplate-to-torque-converter bolts using a box-end wrench or socket.
5. 5

   Support transmission
   Position transmission jack under transmission oil pan with a wood block to distribute load. Raise jack to just contact transmission weight. Secure transmission to jack with safety chain or strap.
6. 6

   Remove crossmember and transmission mount
   Remove the 2 bolts securing transmission mount to crossmember. Remove the 4 bolts securing crossmember to frame rails. Lower transmission jack slightly and remove crossmember from vehicle.
7. 7

   Remove bellhousing-to-engine bolts
   Remove the bellhousing-to-engine block bolts (typically 6 bolts total: 2 upper, 2 middle, 2 lower). On some configurations, upper bolts may be accessible from above near the firewall. On some configurations, there may be an upper bolt accessible from above near the firewall. Support engine with a jack under the oil pan (use wood block) if it begins to tilt. Verified detail (A Ford 302 with C4/FMX bellhousing typically uses 6 bellhousing-to-engine bolts, not 4. This is flagged as an open question; 4 is likely undercounted.): Remove the bellhousing-to-engine block bolts (typically 6 on a Ford 302 with C4/FMX; verify exact count for this application).
8. 8

   Separate transmission from engine
   Carefully pull transmission rearward on transmission jack, ensuring torque converter stays with transmission and does not remain on flexplate. Move transmission rearward until the transmission input shaft and integral bellhousing clear the engine block dowels, then lower and remove from under vehicle. Install a torque converter holding tool or wire to prevent converter from sliding out.
9. 9

   Lock crankshaft and remove flexplate
   Use a flywheel holder tool or wedge a large screwdriver between flexplate teeth and bellhousing to prevent crankshaft rotation. Remove the 6 flexplate-to-crankshaft bolts using a socket and breaker bar. Remove flexplate from crankshaft flange. Inspect rear main seal for leakage and replace if necessary.
10. 10

    Inspect and prepare for installation
    Inspect crankshaft flange for damage, cracks, or excessive runout. Clean crankshaft flange and bolt holes thoroughly with wire brush and solvent. Inspect new flexplate for cracks, especially around bolt holes and ring gear teeth. Verify new flexplate matches original in tooth count and offset.
11. 11

    Install new flexplate
    Position new flexplate on crankshaft flange, aligning bolt holes. Install the 6 new flexplate-to-crankshaft bolts finger-tight. Lock crankshaft with flywheel holder. 63.0 lb-ft (85.0 Nm) Verified detail (Torque specification for flexplate-to-crankshaft bolts on 1972 Ford 302 V8): 63.0 lb-ft (85.0 Nm)
12. 12

    Reinstall transmission
    Apply light coat of high-temp grease to transmission input shaft splines. Ensure torque converter is fully seated in transmission pump (should be recessed approximately 1/2 inch from bellhousing face). Raise transmission on jack and align input shaft with pilot bushing in crankshaft. Slide transmission forward until bellhousing contacts engine block. Do not force transmission; if resistance is met, recheck alignment.
13. 13

    Install bellhousing and mount bolts
    Install the bellhousing-to-engine bolts (typically 6 bolts) and tighten evenly to pull bellhousing fully against engine block. Reinstall crossmember to frame rails with 4 bolts. Install transmission mount to crossmember with 2 bolts. Remove transmission jack.
14. 14

    Install torque converter to flexplate
    Rotate crankshaft to align flexplate with torque converter bolt holes (use the marks made during disassembly). Install the 4 new flexplate-to-torque-converter bolts and tighten in a cross pattern to 63.0 lb-ft (85.0 Nm) while holding crankshaft. Reinstall bellhousing inspection cover if equipped.
15. 15

    Reconnect all components
    Reconnect transmission cooler lines and tighten fittings securely. Reconnect speedometer cable. Reconnect shift linkage and kickdown linkage. Install driveshaft, aligning marks made during removal, and install 4 U-joint strap bolts. Reinstall transmission pan with new gasket.
16. 16

    Refill transmission and verify operation
    Fill transmission through dipstick tube with approximately 5 quarts of Type F ATF initially. After running engine and cycling through gears, add additional fluid to bring level to full mark (total capacity approximately 8-10 quarts depending on C4 or FMX transmission). Start engine and allow to reach operating temperature with transmission in Park. Check for leaks around pan, cooler lines, and rear seal. Shift through all gears while holding brake pedal. Recheck fluid level with engine running in Park at operating temperature and add fluid gradually as needed to bring to full mark on dipstick without overfilling. Verified detail (A C4 or FMX transmission with torque converter holds roughly 9-10 quarts total, but a refill after only dropping the pan (converter not drained) typically requires far less. Since this procedure removed the transmission and converter, the total dry fill is closer to 9-10 quarts for C4; 11 quarts is likely overstated. Also, initial fill should be conservative with level rechecked, not a fixed 11 quarts.): Fill transmission through dipstick tube with approximately 9-10 quarts of Type F ATF (verify exact capacity for C4 vs FMX), adding gradually and rechecking level to avoid overfilling.

Reassembly

1. Torque all fasteners to specification when torque values become available in database.
2. Use new gaskets and seals for all components removed during procedure.
3. Ensure all electrical connectors and linkages are properly reconnected before starting engine.
4. Double-check that torque converter is fully seated before installing transmission to prevent pump damage.

Verification

• Start engine and verify no abnormal noises from bellhousing area.
• Test drive vehicle and verify smooth engagement in all gears with no slipping or harsh shifts.
• Check for fluid leaks around transmission pan, cooler lines, and rear main seal after test drive.
• Verify no vibration at idle or during acceleration that would indicate flexplate imbalance.
• Recheck transmission fluid level after vehicle reaches operating temperature.

More procedures for this vehicle