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Vacuum to the modulator controls both how hard & WHEN this trans shifts.
"T" a vacuum guage into the vacuum line that goes to the modulator & drive the car(watch the gauge inside of the car). Vacuum should be high at idle & with foot off of the fuel pedal. At full throttle there shouldn't be any vacuum. In-between the vacuum should go up OR down depending on pedal position.

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MERCEDES Benz Master Guild Technician (6 TIMES)
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44 years foreign automotive repair
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190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
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