1977 Ford Bronco Automatic TransFACTORY OEM SERVICE PROCEDURE

Ignition Coil Test

With ignition off, check secondary resistance between pin No. 4 and coil tower. Resistance should be 7700-9300 ohms. Check primary resistance between pins No. 1 and 4. Resistance should be 1.13-1.23 ohms. If coil resistance is not within limits, bench test coil using standard testing procedures.

Factory Service Tools

Use the Manual With the Right Hardware

Pair factory procedures with proven DIY tools so the instructions are easier to execute.

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • β€’ You smell fuel, burning insulation, or see smoke.
  • β€’ Brakes feel soft, pull hard to one side, or make grinding noises.
  • β€’ The engine overheats, stalls repeatedly, or misfires under load.
  • β€’ You are missing required tools, torque specs, or safe lifting equipment.
  • β€’ You are not confident in the next step or safety outcome.