My trans only has 3k since rebuilt, won't shift 3rd-4th with vacuum connected, has new vcv 12hg at idle, down to 4 hg at high throttle, mod pressure checked and ok, modulator holds vacuum. I disconnected kickdown switch under pedal, no change. Trans will shift, third to fourth with vacuum disc to trans, but hard shifts, replaced trans filter and pan was clean. valve body spring? working pressure? Trans only has 3k, but that was over 3 yrs.

Vacuum to modulator should drop to "0" inches of vacuum at full throttle.

If not then adjustments on the control valve at the injection pump OR at the modulator transducer are needed.

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how do you adjust vacuum transducer, is that same as vacuum amplifier, round blue plastic with 4 vacuum connections, that feeds modulator

adj vacuum transducer and now have 12hg to around 0hg at vacuum line to trans modulator, still won't shift 3rd to 4th, yet will shift intermittant 3rd to 4th with modulator vacuum line off at transducer. Do I have broken modulator pin? or valve body spring(k2) problem? what im I overlooking.