Uhhh! OK! on that last post! Is he answering someone elses post? Anyway, whole idea of OD is that it freewheels when used and no backpressure from engine for braking. Your engine can idle down. Don't know the recovery time when you reaccelerate, bet there's some gear/operation lag there, shouldn't Bang into drive again tho. I think you can bypass the switches for carb/kickdown and such and use toggles or pushbuttons or something if you don't have all the parts. Not aware of all the tricks, just from what I've read on them here.
