Hyper Mileing

[Langod]

Originally Posted by Da Klugs

Have read the same things re neutral. Not the case on my Audi. Runs at 1100-1200 RPM while in gear and I think the AWD comes into play re the efficiency. In neutral, drops to 800 rpm. Huge difference in the Mpg and the "feel".

Originally Posted by Sancho

This is somewhat more of an instance than the rule, many transmissions dont freewheel while in gear and the slipping is taken up hydraulically etc.

From what I've read, the tranny doesn't freewheels (if I understand what you mean) -- The wife's subaru's RPM is still "normal" for the speed it's going in gear, but like I said it pegs the MPG readout. Moving to actual neutral does drop the RPM to 800 or so, but the MPG readout reads much less.
(According to this short article your car actually uses no fuel whatsoever while coasting in gear.)
I don't know for sure, just reporting what I've read. I'm not a mechanic -- I can understand a manual tranny, but automatic transmissions might as well be magic to me.

And just for giggles, here's an article from Road & Track regarding gas saving tips and myths.