This procedure covers the removal and replacement of the rear engine mount (transmission mount) on a 1966 Chevrolet Corvette equipped with the 327ci V8 engine.

Warnings

Tools required

Parts

• Rear engine mount (transmission mount) × 1 — Use OEM specification

Preparation

1. Park vehicle on level, hard surface and engage parking brake firmly
2. Place wheel chocks behind front wheels
3. Disconnect negative battery cable to prevent accidental starter engagement
4. Allow engine to cool completely if recently operated
5. Inspect rear mount area from underneath to identify corrosion or access constraints

Procedure

1. 1

   Raise and support vehicle
   Raise the rear of the vehicle using a floor jack positioned at the rear differential housing or rear frame crossmember. Raise high enough to provide working clearance underneath. Place jack stands under the rear frame rails just forward of the rear axle. Lower vehicle onto jack stands and verify stability before proceeding.
2. 2

   Locate rear engine mount
   From underneath the vehicle, locate the rear engine mount (transmission mount). This mount is positioned between the rear of the transmission tailhousing and the transmission crossmember. The mount consists of a rubber isolator that bolts to the transmission tailhousing extension and is secured to the transmission crossmember. Verify the exact bolt count and configuration against the factory service manual before disassembly.
3. 3

   Support transmission
   Position a transmission jack or floor jack with a wood block under the transmission oil pan. Raise the jack until it just contacts the pan with slight upward pressure, but do not lift the transmission yet. This will support the transmission weight once the mount is disconnected.
4. 4

   Remove upper mount fasteners
   Using a 9/16" socket and ratchet, remove the 2 bolts securing the upper portion of the rear mount to the transmission tailhousing extension. Support the fasteners as they are removed to prevent dropping.
5. 5

   Remove lower mount fasteners
   Using a 9/16" socket and ratchet, remove the 2 bolts securing the lower portion of the rear mount to the transmission crossmember. You may need to raise the transmission slightly with the jack to relieve tension on these bolts.
6. 6

   Remove rear engine mount
   With all fasteners removed, lower the transmission jack slightly to create clearance. Remove the rear mount assembly from between the transmission and crossmember. It may be necessary to use a pry bar to separate the mount if corrosion has caused binding.
7. 7

   Clean mounting surfaces
   Use a wire brush to clean the mounting surfaces on both the transmission tailhousing and the transmission crossmember. Remove all rust, debris, and old rubber residue to ensure proper seating of the new mount.
8. 8

   Position new rear mount
   Position the new rear engine mount between the transmission tailhousing and crossmember. Use the transmission jack to raise or lower the transmission as needed to align the mount bolt holes with both the transmission and crossmember.
9. 9

   Install upper mount fasteners
   Install the upper mount bolts through the mount into the transmission tailhousing, matching the original fastener arrangement. Start both bolts by hand to ensure proper thread engagement, then snug them with a 9/16" socket but do not fully tighten yet.
10. 10

    Install lower mount fasteners
    Install the lower mount bolts through the crossmember into the mount, matching the original fastener arrangement. Start both bolts by hand, then snug them with a 9/16" socket but do not fully tighten yet.
11. 11

    Adjust transmission position and torque fasteners
    With all four mount bolts installed, use the transmission jack to adjust the transmission to a neutral position where no stress is placed on the mount. The transmission should be level and centered. Torque all mount bolts to the factory specification (verify against the 1966 Corvette service manual) in a cross pattern (alternate between upper and lower bolts) to ensure even load distribution.
12. 12

    Remove transmission support
    Carefully lower and remove the transmission jack or floor jack from under the transmission. Verify the mount is holding the transmission securely and that there is no unusual sagging or misalignment.
13. 13

    Lower vehicle
    Raise the vehicle slightly with the floor jack to unload the jack stands. Remove jack stands and carefully lower the vehicle to the ground.

Reassembly

1. Reconnect negative battery cable
2. Remove wheel chocks

Verification

• Start engine and observe rear mount for excessive movement or vibration
• With engine running, shift through all transmission gears and verify smooth operation without clunking from the rear mount area
• Test drive vehicle and confirm no abnormal vibration or driveline movement under acceleration and deceleration
• Re-inspect mount fasteners after 50-100 miles of driving to ensure they remain tight

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