Press-in vacuum modulator with bracket and O-ring, '72-'82. Vent tube in main case through early '70s. ... C6, or FMX transmission into service, you are free to use Dexron III or Mercon IV fluid.

Transmissions that use a vacuum modulator include the GM Powerglide, TH350, and TH400; and the Ford C4 and C6. These "vacuum modulator-assisted" transmissions will employ a kickdown cable (or an ...

Vacuum Modulator The C4, C6, and FMX transmissions employed throttle valves, or vacuum modulators, to control shift points. Based on intake manifold vacuum, throttle valves adjust transmission ...