Is it really OK to shift into neutral when coasting downhill?
I drive a 92' Dodge Dynasty with an automatic 4 speed transmission. I've read in almost every "fuel saving" instuctable that if you shift into neutral while going downhill, it'll save gas. I told my dad this, excited at the prospect of getting better mileage, and he said that when in neutral, the transmission fluid doesn't circulate in the transmission and it's like the worst possible thing to do. Dad's worked on cars forever, but he learned to work on older ones. I think maybe what he's saying applies to older transmissions or something. Basically, I figure that if it really will cause damage, someone else would have spoken up by now in comments or something.
So, please, settle my nerves. I love my car and don't wanna damage it, but I also want better mileage. Is my dad right or is it safe to shift into neutral?