Adjustable fully automatic vacuum modulator control for automatic transmission having a vacuum modulator

In a multispeed automatic transmission system for vehicles having transmission gears which shift from low to high to low in response to the acceleration and deceleration of the vehicle wherein a vacuum modulator control is mounted in the vacuum line between the vacuum modulator and the intake manifold, the improvement being said vacuum modulator control adapted for mounting at any desired location in the engine compartment comprising a cylinder, a piston slidably positioned in said cylinder, said cylinder having a front end face and a rear end face and a peripheral surface, resilient means in said cylinder for urging said piston toward one of said end faces, stop means in said cylinder remote from said resilient means limiting the amount of movement of said piston in said cylinder, a first port communicating with the interior of said cylinder through said peripheral surface, said first port communicating with the vacuum modulator, second and third ports communicating with the interior of said cylinder through said peripheral surface, said second and third ports communicating with the intake manifold whereby during deceleration air flows into said cylinder through said first port and exits from said cylinder through said second and third ports with said piston being urged against said resilient means and whereby during acceleration air flows into said cylinder through said second and third ports and exits form said first port with said piston being urged away from said resilient means, said piston including a peripheral groove creating flow communication between said first and second ports, and said first and second and third ports and said piston and said peripheral groove being spaced and dimensioned with respect to each other and with respect to said stop means whereby said first and second ports are always in flow communication with each other and open ranging from a fully open to a bleed condition regardless of the position of said piston and said third port is always open regardless of the position of said piston.