Here's a general outline. Specific steps may vary slightly depending on the exact transmission type (manual or automatic) in your 1981 Corvette. Always consult a factory service manual for your specific vehicle for precise instructions and torque specifications.
Tools You'll Likely Need:
* Jack and Jack Stands: Essential for safely working under the car.
* Wheel Chocks: For added safety.
* Socket Set and Wrenches: Various sizes, including those specifically sized for transmission bolts.
* Transmission Jack (Recommended): Makes the job significantly easier and safer.
* Torque Wrench: To ensure proper tightening of bolts.
* Pry Bar (Possibly): May be needed to help separate components.
* New Speedometer Drive Gear: Ensure you get the correct part for your transmission.
* Shop Rags or Paper Towels: To clean up any spilled fluids.
* Penetrating Oil: May help loosen stubborn bolts.
* Factory Service Manual: Absolutely crucial for detailed instructions and torque specs.
General Steps (Consult your service manual for specific details):
1. Safety First: Disconnect the negative battery terminal. Secure the vehicle on jack stands with wheel chocks in place.
2. Access the Transmission: This usually involves removing the appropriate driveshaft. You'll need to support the transmission (especially important with an automatic). A transmission jack is highly recommended. Your service manual will show you how to safely remove the driveshaft and support the transmission.
3. Locate the Speedometer Cable and Drive Gear: Trace the speedometer cable from the instrument cluster back to the transmission. The drive gear is usually located on the output shaft of the transmission.
4. Disconnect the Speedometer Cable: Carefully disconnect the speedometer cable from the drive gear. Take note of how it's connected to avoid problems during reassembly.
5. Remove the Old Drive Gear: This often involves removing a retaining clip or ring. Sometimes the gear is pressed onto the shaft; you may need a gear puller. Your service manual will specify the proper removal method.
6. Install the New Drive Gear: Carefully install the new drive gear, ensuring it's seated correctly. If it's a press-fit, ensure it's properly seated and aligned.
7. Reconnect the Speedometer Cable: Reconnect the speedometer cable to the new drive gear.
8. Reassemble Everything: Carefully reassemble the driveshaft and transmission in the reverse order of removal. Use the correct torque specifications from your service manual.
9. Lower the Vehicle: Carefully lower the vehicle from the jack stands.
10. Test the Speedometer: After reassembly, test the speedometer to ensure it's functioning correctly. An inaccurate reading could indicate an improperly installed gear or another issue.
Disclaimer: This is a simplified overview. Incorrectly performing any of these steps can result in transmission damage, injury, or vehicle malfunction. Always consult a factory service manual specific to your 1981 Corvette and, if you are unsure about any step, seek professional assistance from a qualified mechanic. They have the specialized tools and experience to do this job safely and correctly.
