Replace the pilot bearing (or bushing) in the crankshaft that supports the transmission input shaft. Requires transmission and clutch assembly removal.

Warnings

Tools required

Parts

• Pilot bearing × 1 — Use OEM specification for 327ci V8
• Clutch disc × 1 — Recommended replacement with pilot bearing
• Clutch pressure plate × 1 — Recommended replacement with pilot bearing
• Clutch release bearing × 1 — Recommended replacement
• Transmission input shaft seal × 1 — Inspect and replace if worn

Preparation

1. Park vehicle on level surface and set parking brake
2. Disconnect negative battery cable
3. Raise vehicle and support securely on jack stands under frame rails
4. Allow exhaust system to cool completely if vehicle was recently driven
5. Remove exhaust system from manifolds back to clear transmission removal (unbolt from exhaust manifolds and support/remove as needed)
6. Mark driveshaft-to-differential flange orientation for reinstallation
7. Drain transmission fluid if desired to minimize spillage (optional)

Procedure

1. 1

   Disconnect driveshaft
   Remove the 4 U-bolts or bolts securing the driveshaft to the rear differential pinion flange. Carefully slide the driveshaft rearward to disengage the front yoke from the transmission output shaft. Support the driveshaft and remove it from under the vehicle. Inspect the U-joints while accessible. Verified detail (U-joint strap/U-bolt torque on this driveshaft is typically in the 15-20 ft-lbs range, which is plausible, but should be verified against the GM service manual for the specific U-joint retention type used on the 1966 Corvette independent rear suspension.): Install the driveshaft U-bolts or strap bolts at the differential flange and torque to specification (verify against the GM service manual for the 1966 Corvette, typically around 15-20 ft-lbs)
2. 2

   Disconnect shift linkage and electrical connections
   Disconnect the shift linkage from the transmission side cover. On 4-speed transmissions, this typically involves removing the shift rods at their connection points. Disconnect the reverse light switch wiring connector if equipped. Label connections if necessary for reinstallation.
3. 3

   Disconnect clutch linkage
   Disconnect the clutch fork return spring. Remove the clutch fork pushrod from the clutch cross shaft. On 1966 models, this is typically a solid linkage system from the clutch pedal through the frame to the bellhousing fork.
4. 4

   Remove bellhousing inspection cover
   Remove the 2 bolts securing the lower bellhousing inspection cover. This provides access to view the clutch and flywheel assembly and will aid in transmission removal.
5. 5

   Support transmission
   Position a transmission jack under the transmission pan. Secure the transmission to the jack with a safety chain or strap. Raise the jack slightly to take the weight off the transmission mount but do not lift the transmission.
6. 6

   Remove transmission mount
   Remove the 2 bolts securing the transmission mount to the transmission extension housing. Remove the bolts securing the transmission mount to the crossmember. Remove the transmission mount. Note the orientation of any shims or spacers for reinstallation.
7. 7

   Remove bellhousing bolts
   Remove the 6 bellhousing-to-engine block bolts. These are typically located at the top and sides of the bellhousing. Access may be difficult for upper bolts and may require working from above through the passenger compartment area or with extensions from below.
8. 8

   Remove transmission and bellhousing assembly
   With all bolts removed and transmission supported on jack, carefully slide the transmission rearward away from the engine. Keep the transmission level and aligned with the input shaft to avoid damaging the clutch disc or pilot bearing during removal. The input shaft must be withdrawn straight from the pilot bearing. Once clear of the clutch assembly, lower the transmission jack and remove transmission from under vehicle. On this vehicle the transmission bolts to the rear of a separate bellhousing. First remove the transmission from the bellhousing, then unbolt and remove the bellhousing from the engine block separately.
9. 9

   Remove clutch assembly
   Mark the pressure plate and flywheel for orientation if reusing the pressure plate. Loosen the 6 pressure plate bolts gradually in a criss-cross pattern to prevent warping the pressure plate. Remove the bolts completely and remove the pressure plate and clutch disc. Inspect both for wear, glazing, or oil contamination.
10. 10

    Remove pilot bearing
    Inspect the pilot bearing in the center of the crankshaft. Using a pilot bearing puller or slide hammer with internal puller jaws, engage the tool inside the bearing. Apply steady pulling force to extract the bearing from the crankshaft bore. If a puller is not available, an alternative method is to pack the bearing cavity with heavy grease and use a close-fitting dowel or old input shaft to hydraulically force the bearing out, but this is less controlled.
11. 11

    Clean and inspect crankshaft bore
    Clean the pilot bearing bore in the crankshaft thoroughly with brake cleaner and a clean rag. Use a wire brush if necessary to remove any rust or debris. Inspect the bore for damage, scoring, or excessive wear. The bore should be smooth and free of defects. Check that the new pilot bearing fits the bore properly before installation.
12. 12

    Install new pilot bearing
    Lightly lubricate the outer diameter of the new pilot bearing with clean engine oil (do NOT pack the bearing with grease if it is a sealed bearing; use light grease only on the inner needle surface if it is an open needle bearing type). Using a pilot bearing installation tool or appropriately sized deep socket that contacts only the outer race of the bearing, drive the bearing squarely into the crankshaft bore. Drive it in until it is seated flush or slightly recessed to the depth mark in the bore, typically 1/8 to 1/4 inch below the surface. Ensure the bearing is installed straight and fully seated.
13. 13

    Inspect and prepare clutch components
    Inspect the flywheel surface for heat checking, scoring, or glazing. Resurface or replace if necessary. If installing a new clutch disc and pressure plate, ensure they are the correct specification for the 327 engine and transmission. Clean the flywheel surface and pressure plate mounting surface with brake cleaner. Inspect the clutch release bearing and fork for wear; replace as needed.
14. 14

    Install clutch disc and pressure plate
    Position the clutch disc against the flywheel with the protruding hub side (longer side of hub) facing toward the transmission. Insert a clutch alignment tool through the clutch disc hub and into the new pilot bearing to center the disc. Position the pressure plate over the clutch disc, aligning any marks made during disassembly if reusing. Start all 6 pressure plate bolts by hand. Tighten the bolts gradually in a criss-cross pattern to draw the pressure plate down evenly. Torque bolts to specification (verify against the GM 1966 service manual for your specific pressure plate, typically around 35 ft-lbs). Leave the alignment tool in place until the transmission is ready to install.
15. 15

    Install transmission and bellhousing
    Apply a light coat of high-temperature grease to the transmission input shaft splines and the clutch release bearing contact area on the input shaft bearing retainer. Raise the transmission on the transmission jack and align it with the engine. Carefully guide the input shaft through the clutch disc hub (the alignment tool should still be in place). Slowly push the transmission forward while rotating the output shaft slightly if needed to align the input shaft splines with the clutch disc splines. Once the input shaft is through the clutch disc, remove the alignment tool from the front and continue pushing the transmission forward until the bellhousing mates fully with the engine block. Install the 6 bellhousing bolts and tighten to specification (verify torque against the GM service manual, typically around 50-55 ft-lbs). Reinstall the transmission mount and crossmember, then lower the transmission jack.

Reassembly

1. Reinstall the bellhousing inspection cover with its 2 bolts
2. Reconnect the clutch fork pushrod and return spring to the clutch cross shaft
3. Reconnect the shift linkage to the transmission in the proper positions
4. Reconnect the reverse light switch wiring connector if equipped
5. Apply a small amount of grease to the driveshaft slip yoke splines, then reinstall the driveshaft, aligning the marks made during disassembly
6. Install the driveshaft U-bolts or bolts at the differential flange and torque to specification (typically 15-20 ft-lbs)
7. Reinstall the exhaust system to the manifolds with new gaskets if needed
8. Refill transmission with proper fluid if drained (no fluid was specified as drained in this procedure)
9. Reconnect the negative battery cable

Verification

• Start the engine with the clutch pedal depressed and verify no abnormal noises from the bellhousing area
• With engine running, verify smooth engagement into all gears with clutch pedal operation
• Test drive the vehicle and verify smooth clutch engagement and disengagement with no chatter, slipping, or grinding
• Verify no vibration from the driveshaft during acceleration and deceleration
• Check for any fluid leaks around the transmission and bellhousing after test drive
• Verify clutch pedal feel and engagement point are normal and consistent

More procedures for this vehicle