The lines in the sound definition file defined as TRANNY-SAMPLE MIX will not play "only when" AI is actively driving your vehicle. Thouse lines can be found in sfx files like: VS_INSIDE_COAST_TRANNY_1 VS_INSIDE_COAST_TRANNY_2 VS_INSIDE_POWER_TRANNY_1 VS_INSIDE_POWER_TRANNY_2 VS_OUTSIDE_COAST_TRANNY_1 VS_OUTSIDE_COAST_TRANNY_2 VS_OUTSIDE_POWER_TRANNY_1 VS_OUTSIDE_POWER_TRANNY_2
