The 1990 Chevy Lumina 3.1L doesn't have a separate component called a "transmission modulator." The function of a modulator (which adjusts shift firmness and timing based on throttle position and vehicle speed) is integrated into the
transmission's valve body itself. There's no external, easily accessible modulator to replace or adjust.
If you're having transmission issues, the problem likely lies within the valve body, the governor, or other internal transmission components. You'll need a qualified transmission mechanic to diagnose and repair the problem.
