ok so i put a speed density 305A/T in on of my project cars. bought a nice aftermarket harness (howell, those guys are awesome) car runs great but my question pertains to the trans, (yes i know there is a transmisson section but this pertains directly to TPI) does the computer need a signal from the trans(donor car was an electric speedo car) because the aftermarket harness has provisions for that spot on the trans but it only goes to the computer. i didn't know if the computer made adjustments to its tables based on the speed of the car(ie speed density) i need a mechanical output....anybody shed some light for me here?

 

The ECM uses the signal from the VSS so it knows what speed car is doing for TCC lockup and for when the car is declerating.May be slow to idle down coming to a stop without signal