Oregon Performance Transmission has a large selection of vacuum modulators for all makes and models of automatic transmissions. The vacuum modulator in your transmission should be replaced during every rebuild. However, we find that in some older vehicles, the diaphragm within the modulator can fail causing non-shifting situations or transmission fluid to leak out of the transmission. At that point, the modulator will need to be replaced for proper transmission function. Browse below through our selection of vacuum modulators, many of which are adjustable, allowing you to fine tune your shift points and shift firmness.