Continuing to troubleshoot shift flare issues, I put a Mityvac T in the vac line as indicated by the arrow in the attached pic. This is up in the rear driver's side of the engine compartment.

At idle I had a steady 18 inches of Hg vacuum, which dropped slightly when I revved to 2,000 rpm. Is this about right?

I then switched off and separated the line and tested with the Mityvac. The line going into the bulkhead behind the brake booster held vac for over a minute with no problem. The line heading for the intake manifold banjo bolt would not hold vac - no doubt due to all the air in the manifold?

I am concluding next step is to test the modulator valve on the transmission... if anyone can comment on whether I am on the right track ... please do so...

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