[Kodak]

This thought occurred to me today: Has anyone ever tried to create a vehicle with an adjustable final drive ratio?

I know you may be thinking that it's silly (just build a better transmission with more gears). I'm just thinking along the lines of a pickup truck that is sometimes heavily loaded, and sometimes empty. It may need a 4.10 rear end for hauling, but not for highway cruising.

Of course, the mechanics of temporarily disengaging the drive shaft would be complicated...I'm just thinking theoretically right now.