Complete removal and replacement of the torque converter in a 1966 Corvette with 327 V8, requiring transmission removal and stall speed verification.

Warnings

Tools required

Parts

• Torque converter × 1 — Use OEM specification or high-stall performance unit
• Transmission pan gasket × 1 — Powerglide or Turbo Hydramatic 400 pan gasket
• Transmission filter × 1 — Use OEM specification
• Flexplate-to-torque converter bolts × 3 — 7/16"-20 grade 8
• Transmission mount bolts (if corroded) × 2 — Use OEM specification
• Driveshaft U-joint straps or bolts × 1 — Use existing hardware unless damaged

Fluids

• Dexron III ATF — 11.5 qt

Preparation

1. Park vehicle on level surface and engage parking brake.
2. Disconnect negative battery cable.
3. Raise vehicle and support securely on four jack stands at frame rails.
4. Remove exhaust system from manifolds back to rear axle for clearance (unbolt at flange connections).
5. Mark driveshaft and rear axle yoke for proper reassembly alignment.
6. Drain transmission fluid by removing pan (no drain plug on most 1966 applications).
7. Allow engine and transmission to cool completely if recently operated.

Procedure

1. 1

   Remove driveshaft
   Remove the 4 bolts or U-bolts securing the rear U-joint straps to the differential yoke. Support driveshaft and slide rearward to disengage slip yoke from transmission tailshaft. Lower driveshaft and remove from vehicle. Inspect slip yoke seal and U-joints for wear.
2. 2

   Disconnect transmission controls and cooling lines
   Disconnect shift linkage at transmission lever (Powerglide uses single rod, TH400 uses rod linkage at the manual shift lever). Disconnect kickdown linkage or modulator vacuum line as applicable. Place drain pan under transmission cooler line fittings and disconnect both cooler lines from transmission case using line wrench to prevent rounding. Plug lines and transmission ports to prevent contamination.
3. 3

   Remove transmission crossmember
   Support transmission with transmission jack, centered under the pan. Remove the 2 transmission mount-to-crossmember bolts. Remove the 2 or 4 crossmember-to-frame bolts and lower crossmember from vehicle. Maintain transmission jack support.
4. 4

   Access torque converter bolts
   Working through the starter opening or inspection cover (remove inspection cover by removing 2-3 bolts securing it to bell housing lower edge), locate the flexplate-to-torque converter bolts. There are 3 bolts evenly spaced around the converter. Use flywheel turner on crankshaft bolt or manually rotate engine with breaker bar to bring each bolt into accessible position.
5. 5

   Remove torque converter mounting bolts
   Remove all 3 flexplate-to-torque converter bolts while rotating engine to access each bolt. Mark flexplate and converter orientation if converter is being reused. Push torque converter rearward toward transmission to ensure it disengages from flexplate.
6. 6

   Remove transmission-to-engine bolts
   Remove the 6 bell housing bolts securing transmission to engine block. Note bolt lengths and locations as they may vary. Support transmission securely on jack as it will become free once bolts are removed.
7. 7

   Separate transmission from engine
   Verify all connections are disconnected and all bolts removed. Carefully slide transmission rearward on jack, keeping it level and aligned with engine to prevent binding. Move transmission approximately 2-3 inches rearward until input shaft clears engine block and bell housing clears alignment dowels. Install C-clamp or strap through bell housing to secure torque converter and prevent it from sliding out during removal.
8. 8

   Lower and remove transmission
   Carefully lower transmission jack while guiding transmission down and rearward. Navigate around crossmember mount points and frame rails. Once clear of vehicle, roll transmission to work area. Keep transmission nose-up to prevent fluid loss and converter from sliding out.
9. 9

   Remove old torque converter
   With transmission on bench and nose elevated, remove C-clamp or holding device. Carefully slide torque converter forward and out of transmission bell housing. Torque converter should slide straight out once disengaged from pump. Inspect transmission front pump seal, pump bushing, and input shaft splines for damage or excessive wear.
10. 10

    Prepare new torque converter
    Inspect new torque converter for shipping damage and verify correct stall speed and bolt pattern. Add 1-2 quarts of fresh Dexron III ATF into converter through hub to pre-fill. Rotate converter to distribute fluid internally. Verify converter pilot hub is clean and free of burrs that could damage pump seal.
11. 11

    Install new torque converter
    Align converter hub with transmission pump and carefully slide converter into bell housing. Rotate converter while pushing forward to engage pump drive slots. Converter must fully seat with three distinct engagements: outer gear to pump, inner hub to stator support, and drive lugs to pump drive. Measure from bell housing mounting face to converter ear/lug mounting pad; distance should be approximately 1-1/8 to 1-1/4 inches, confirming full engagement. If converter sits proud of this dimension, it is not fully seated and will damage pump upon installation.
12. 12

    Reinstall transmission to engine
    Position transmission on jack and raise into position, aligning with engine block. Install C-clamp through bell housing to prevent converter from sliding forward. Slide transmission forward, keeping it level and aligned with engine centerline. Rotate converter as needed to align with flexplate. Transmission should slide fully forward until bell housing contacts engine block without excessive force. If binding occurs, check for misaligned dowel pins or converter not fully seated.
13. 13

    Install bell housing bolts
    Install all 6 bell housing bolts finger-tight, ensuring proper length bolt in each location. Tighten bolts in criss-cross pattern. Verify transmission mates flush to engine block before final tightening. Remove converter holding clamp once transmission is secured.
14. 14

    Install torque converter-to-flexplate bolts
    Rotate engine to access each of the 3 bolt holes in flexplate through inspection opening. Align converter lugs with flexplate holes (converter may need slight rotation to align). Install all 3 bolts and tighten in star pattern while rotating engine. Verify converter rotates freely by hand after bolts are tight.
15. 15

    Reinstall crossmember and mount
    Raise transmission slightly with jack to align with crossmember. Install crossmember to frame using original bolts and tighten. Install transmission mount bolts and tighten. Remove transmission jack.
16. 16

    Reconnect all components
    Reconnect transmission cooler lines and tighten fittings securely. Reconnect shift linkage and adjust as necessary per factory specifications. Reconnect kickdown linkage or modulator vacuum line. Install inspection cover using original bolts. Reinstall driveshaft, aligning marks made during removal, and torque U-joint strap bolts.
17. 17

    Reinstall exhaust system
    Reinstall exhaust system at manifold flanges and all hanger points. Ensure proper clearance around transmission, driveshaft, and chassis components. Tighten all exhaust fasteners.
18. 18

    Fill transmission with fluid
    With vehicle still raised, add approximately 6 quarts of Dexron/Mercon-compatible ATF through dipstick tube using funnel. Lower vehicle to ground. Add additional fluid to bring level to 'ADD' mark on dipstick. Do not overfill at this stage.
19. 19

    Initial startup and fluid level check
    Reconnect battery negative cable. Start engine and allow to idle in PARK. Check underneath vehicle for leaks at cooler lines, pan gasket, and converter area. With engine at idle, shift through all gear ranges, pausing 2-3 seconds in each position, then return to PARK. Check fluid level with engine running and add fluid as necessary to bring level to 'FULL' mark. Total capacity is approximately 9 quarts for Powerglide or 12-13 quarts for TH400, including converter and cooler; verify against the specific transmission fitted.

Reassembly

1. Torque all fasteners in specified sequence where applicable, particularly bell housing bolts and converter mounting bolts.
2. Verify transmission cooler lines are tight and properly routed without kinks or sharp bends.
3. Adjust shift linkage per factory procedure to ensure proper gate detents and starter safety in PARK and NEUTRAL.
4. If kickdown linkage is used, adjust per factory specifications for proper wide-open-throttle downshift operation.

Verification

• With engine running, verify smooth engagement in all forward gears and reverse with no excessive slippage or harshness.
• Check transmission fluid level with engine at operating temperature and in PARK; level should be at 'FULL' mark on dipstick.
• Perform test drive and verify proper shift points, no slipping, and correct torque converter lockup characteristics (if equipped).
• Verify no leaks from converter hub seal, cooler lines, pan gasket, or driveshaft seal after test drive.
• Check for abnormal noises such as rattling (loose converter bolts) or whining (low fluid level or air in system).
• For performance converters with higher stall speed, verify stall RPM matches converter specification using brake-stall test (performed carefully and briefly to avoid transmission overheating).

More procedures for this vehicle