[Christ]

Without a tach, it's a little harder, but you have the ear for the car as it is, so you tell him where to set the pedal, then teach him to identify the appropriate speed to shift by the sound of the car, NOT the speedometer.

Shifting by the speedometer leaves you SOL if just about anything happens where you can't use/see the speedo, and doesn't teach the driver anything about the car at all. Driving manuals is preferred by my immediate family because you have to be in sync with the car to be doing it correctly, and if you can't identify shift points by vehicle sound, you're definitely not "in sync" with your car.