How to Wire an Hour meter?

How to wire an hour meter?????

Hey Scotty; How would I wire an Hour Meter into a Modern Car; If I ONLY wanted it to count when the Transmission was in "Drive"? Excuse the Farmer; in me; "Hours; it's just the Way I was raised" Would this even be Possible?

anything's possible, you would wire it to the power wire that turns the D on when you put it in drive