1. Check the Linkage:
* Column Shift Linkage: The most likely culprit is a problem with the linkage that connects the transmission shift lever to the indicator on the steering column. This linkage is usually made of cables or rods.
* Disconnection: The cable or rod might have come loose or disconnected at either the transmission end or the column end. Inspect carefully. You'll likely need to access the linkage under the dash and possibly from underneath the truck.
* Binding or Damage: The linkage might be bent, kinked, rusted, or otherwise damaged, preventing it from moving freely and accurately reflecting the transmission's position. Look for any signs of wear, tear, or rust.
* Adjustment: Even if connected, the linkage might need adjustment. There might be adjustment screws or nuts at connection points that allow you to fine-tune the indicator's position. However, be extremely careful when adjusting as you can easily over-tighten or damage components.
* Transmission Shift Linkage: While less common, issues within the transmission itself affecting the linkage to the steering column could also exist. This is far more involved and might require professional assistance.
2. Check the Indicator Unit:
* Internal Damage: The indicator unit itself might have a broken or worn-out gear, a jammed needle, or other internal damage. This is less common than linkage problems but possible. Accessing the indicator requires removing the steering column bezel and possibly more disassembly. This is a more delicate process.
3. Repair Steps (General):
* Disconnect the Battery: Before starting any work, disconnect the negative battery terminal to prevent electrical shorts.
* Access the Linkage: You will need to access the linkage mechanism. This often involves removing parts of the steering column shrouding, knee bolster, and potentially other components under the dash. Consult a repair manual specific to your 1976 Chevy truck model to determine the appropriate steps for disassembly.
* Inspect for Damage: Once accessible, carefully inspect the entire linkage for damage, loose connections, or binding.
* Repair or Replace: If you find damage, attempt repair (e.g., straightening bent rods, replacing damaged cables or parts) or replacement if necessary.
* Re-assembly: Reassemble carefully, ensuring all connections are secure and the linkage moves freely.
* Test: Reconnected the battery, test the gearshift and see if the indicator moves appropriately.
4. Seeking Professional Help:
If you are not comfortable with auto repair or the disassembly of the steering column, it's best to take your truck to a qualified mechanic experienced in working on older vehicles. Steering column work can be tricky, and an incorrect repair could lead to further problems.
Important Note: A 1976 Chevy truck repair manual specific to your model and trim is extremely helpful. It will show you detailed diagrams, procedures and torque specs necessary for this repair. You can find these manuals online (eBay, Amazon) or at auto parts stores. Using a repair manual is strongly recommended to avoid further damage.
