1976 Ford Courier Automatic TransFACTORY OEM SERVICE PROCEDURE

Throttle Modulator Diaphragm Check

  1. Disconnect manifold vacuum hose from solenoid valve at diaphragm unit. Plug end of hose. Using an external vacuum source, apply 19 in. Hg of vacuum to the diaphragm. Check for throttle arm movement.
  2. If throttle does not move, check linkage and repair or replace as necessary. If vacuum leakage from 19 in. Hg to 12 in. Hg of vacuum takes less than 2 seconds, replace diaphragm unit.
  3. Check position of adjusting screw on diaphragm housing. Ensure adjusting screw does not interfere with mechanically lock-out movement of throttle linkage.
  4. Release external vacuum from diaphragm. Diaphragm should retract to original position within 5 seconds. If not, replace throttle modulator. Remove plug from vacuum hose and reinstall on diaphragm.
Factory Service Tools

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When to See a Mechanic

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

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

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