Coasting in neutral or with clutch down?

[Ptero]

It depends on your type of automatic. Some pumps are driven by the engine, others by the wheels. A friend of mine burned up his high ratio gears by coasting 5 miles, once, so it's good to know for sure which you have. The dealer should know. But my experience with people who coast automatics has always been that they NEVER know.

[LeanBurninating]

but when your coasting the wheels are still turning the output shaft of the tranny... even if the engine is off....

[PaleMelanesian]

The information is easily found in the owner's manual.

[cfg83]

Ptero -

Our rule of thumb is that if the automatic can be flat-towed (i.e. Winnebago scout-ship), it's good to go.

[EDIT: LeanBurninating corrects me below. I read the post without reading the previous post]

CarloSW2

[LeanBurninating]

Originally Posted by Ptero

...
COASTING IN NEUTRAL WITH AUTOMATIC TRANSMISSIONS
Never do this. Always "coast" in drive. If you have been doing this in a car that the manual does not specifically say can be "flat towed," you should sell your car.
...

Im pretty sure that is exactly what he said.

[DIMS]

I see all kinds of opinions on coasting in neutral or in gear but no real data for the bystandard . I realize a lot of people come to some conclusion with their own data and testing but do not share the data only the opinion. I figured I would measure how much I coast on a 6.5 mile commute. the answer is .8 miles. For me coasting in gear is the better option. In gear for the .8 miles I burn 0 fuel but if I use neutral for the same distance .4 miles I burn ~.55 gallons per hr. and for the remaining .4 miles I burn .16 Gallons per hr. Though it is not much over all, it makes better sense for me to use the 5th gear and not neutral. I do not drive on the Highway or the Freeway, it is all ~20 to 45 mph back roads.

I’m curious how much those that choose neutral or in gear actually coast and what kind of commute it is??

[PaleMelanesian]

I coast at least 5, maybe 6 miles of my 10 mile commute. Leaving it in gear would cut that in half, and require 2-3 more miles of engine running time. That would cost a fair chunk of fuel.

[99metro]

Flat-towing means engine off and all 4 wheels on the ground while being towed. Most all automatics can't be flat-towed without modification (such as driveshaft disconnects). With the engine running and all 4 wheels on the ground, then automatics can be flat-towed in neutral - although you'd want someone in the car to make sure it didn't kick into drive, etc.

PaleMelanesian - I'm with you on that. My pulse and glides would be a joke.

[Ptero]

Using a dash-mounted cumulative sum calculator, I kept a running total of coasting miles on a 2000 mile highway trip. Although I did not pulse and glide, I coasted every downhill from 60 down to 45 or so, depending on traffic, and was amazed to find my coasting miles totalled nearly 400 - or 20%. A better way to record this would be to link odometer output to the neutral light, then pulse and glide would be recorded and the driver would not be distracted.

[DIMS]

Originally Posted by PaleMelanesian

I coast at least 5, maybe 6 miles of my 10 mile commute. Leaving it in gear would cut that in half, and require 2-3 more miles of engine running time. That would cost a fair chunk of fuel.

That really is amazing! I'm going to do more comparisons with in gear vs neutral 35mph to 15mph coast downs. What kind of commute is this 65mph Zones and is it total or 1 way?