centurion70

No, I read it right. The "rate" of fuel consumption to which I referred could be (and usually is) zero when coasting.

If your point is that the engine consumes a small amount of fuel when coasting in Neutral (as opposed to coasting in Drive) to maintain idle speed, then yes, I agree with you, and I made that point in my subsequent post.

snagitseven

I know you were referring to the "clunk" but I think you hit the nail on the head with your title of the thread: "Don't do this". For all the safety reasons mentioned previously if nothing else.

81Coupe

I have an experience with my old M-Class, that may or may not be relevant with the Audi gearbox.

There is a one mile stretch of road between two stop lights near my home, whose slight down slope is such that I can maintain a almost constant 35 mph speed (only) if I put the car in neutral. So that's what I always did. One day I needed to stomp on the brakes to avoid an accident. Then I put the car back in gear and applied gas. But the car revved in neutral, and the gearbox won't engage. I tried again and it revved again. For some 30 harrowing seconds, the car almost coasted to a stand still before getting back in gear.

In retrospect, I guess what happened was that I applied the gas a little too early, and since the engine was spinning above idle, the computer decided not to engage the gearbox. And in my panic, I had not waited long enough for the engine to clam down before trying the gas pedal again, so the computer and I kept waiting for each other.

The moral of the story is, with all these computerized drive-by-wire systems in a modern day car, you can never count on the car to get right in gear when you put it in a situation it was not designed for. A computer not programmed for coasting in neutral can and will behave unexpectedly.

I no longer think coasting in neutral is something one can safely do with a modern day car.

Jazzy

I thought I remember reading something in the manual that says not to do coast in N. It's been a long day so don't have the energy to go look for it.

stash64

Checked out the manual and could not find anything explicitly warning against shifting into Neutral while driving. It does state that when stationary or at speeds less than 1 mph, you must apply the brake to shift into Neutral.

I also looked at all the warnings and notes for the transmission and found these three interesting:

Warning: Never shift into R or P while driving. (No mention of N).

Note: Coasting downhill with the transmission in N and the engine not running will result in damage to the automatic transmission and possibly the catalytic converter.

Tips: If you accidentally select N while driving, take your foot off the accelerator pedal immediately and wait for the engine to slow down to idle before selecting D/S.

The Tip seems to suggest that this transmission does not like being shifted into Neutral while driving. I definitely had my foot off the gas prior to "purposely" selecting N, and I'm fairly certain the engine was already at idle when I shifted and got the jolt. I had no problem shifting back to D after the jolt.