Neutral to drive?

[yi5hedr3]

Check with a ScangaugeII. You may have "fuel-cutoff" in which case you will burn more gas coasting in neutral vs in gear!!

[GeneW]

Originally Posted by mhmitszach

Would putting my car in neutral down a hill and then back into drive have any ill effects on my transmission?

Some automatic transmissions use the engine to run the pump. If you shut off t the engine you will damage the transmission from lack of cooling and lack of lubrication.

Gene

[kamesama980]

Originally Posted by GeneW

Some automatic transmissions use the engine to run the pump. If you shut off t the engine you will damage the transmission from lack of cooling and lack of lubrication.

Gene

all do unless you've discovered one with an electric pump. otherwise you won't get line pressure to push the clutches and plates together to start moving. Some transmissions just have an auxiliary unit on the putput shaft, splash/dip lube system, or something to keep them from burning up while being flat towed.

[WRXGuy1]

Efficiency wise, I just did a test with my new ScanGuage on my 2007 Camry, and when I was coasting down a hill at around 40MPH, it said I was using around 0.40-0.60GPH in drive, however when I put it in neutral is went down to about 0.25-0.35GPH. And of course the RPM's dropped from around 1200-1500 in D, down to about 600-750 in N.

[gto78]

I've tried something similar to this test in my 98 explorer. Everyday while driving to work I take my foot off the gas at the same place before my "Exit" ramp of the turnpike. I always coast from 70mph down to about 35 mph which happens in the middle of the exit ramp left turn/overpass. Then I finally step on the gas again to maintain 35mph until I reach the tollbooth. This is about a 1/3 mile distance.

When I try the same thing except put the truck in neutral I can coast the entire distance without having to step on the gas, in fact I have to slow down at the toll booth because I'm still going too fast. I basically get double the coast time in neutral. I realized from this experiment that the aerodynamic drag of my explorer wasn't nearly as bad as I thought, especially below 55 mph.

[GasSavers_Bruce]

Originally Posted by VetteOwner

no just dont slip it into reverse or park. its called an automatic for a reason.

Don't push the shift lock button (or pull forward on a column shift) when shifting between Neutral and Drive. This will prevent accidental shifts into Park, Reverse or the Low range. Just push the shifter back and forth.

Better yet, spend some time playing with the shift lock button and lever positions while the car is parked with the engine off to understand how it works. You should only need to depress the shift lock button to shift out of Park or to shift into Reverse, Park or the Low gears.

Going from Reverse to Drive only requires pushing the shifter back without using the shift lock button; Low to Drive is just pushing the shifter forward (to Neutral), then back (to Drive). You can also go from Reverse to Neutral using the opposite motion.

Knowing how the shift lock button works can save your butt when you're trying to panic stop on ice, because you need to have it in Neutral for the shortest stopping distance.

[GasSavers_RoadWarrior]

Jaguar S Types quite likely have the Ford EEC in, this is known to have injector cutout at speeds down to 1800 RPM (Might depend on application and torque convertor stall) then it adds fuel again to keep the motor running. Therefore if you coast in neutral in an EEC car down to a point where it needs 1800rpm or perhaps a little less to pick up again, you're probably using more gas than coasting in gear. Coasting down to a standstill, you might even be better off dropping gears manually rather than neutral coasting, keep it over about 1800. On roads that aren't in the middle of nowhere, you can't generally get away with a full coast down in neutral without severely pissing everyone off anyway, off-ramp coastdowns in gear and toward red lights doesn't seem to annoy people too much though.

By the way, many Ford transmissions DO NOT have a standard service interval specified for the transmission, this is why they die. Do maintenance per the severe service schedule and they live a lot longer (Basically just change the fluid every 30K or so) expecting trannies to go a lifetime on one fill is a bit optimistic IMO.

[k8crd]

Originally Posted by yi5hedr3

Check with a ScangaugeII. You may have "fuel-cutoff" in which case you will burn more gas coasting in neutral vs in gear!!

Can you check with a Scan-gauge II if your vehicle has fuel cutoff?

If yes, what is the procedure?

Paul

[GasSavers_Minger]

the mpg guage will read 9999 if you have cutoff.

[popimp]

Originally Posted by Rick Rae

Consider adding a safety warning or disclaimer when you're talking about an automatic transmission.


Absolutely incorrect. The most savings come from the neutral glide -- killing the engine is incremental.

If you don't believe that, do the math for yourself. Assume for the sake of argument that an engine burns 0.3GPH at idle. If a driver can manage to neutral glide 25% of the time (and I'd say that's optimistic), 0.075 gallons per hour is the maximum additional fuel savings.

I believe in incremental savings -- a percent here, a half percent there adds up. I'm only saying that leaving the engine on does not make the technique worthless.


... unless A) your vehicle has a lockout (my VW won't go into reverse if the brake pedal isn't depressed) or B) you pay attention to what you're doing.

Rick

P.S. As long as I'm mentioning disclaimers, I should point out that driving in neutral is technically illegal in a lot of places. Check your applicable laws and make informed decisions.

I'll have to disagree. I moved from Mississippi to Califronia back in October. Doing Neutral glides on the highway for 350 miles each day. The Scan Gauge 2 was convinced that I was getting 30 MPG. When I filled up I got 26 the first day and 24 the next. The point is don't take the Scan Gauge's word as gospel. The true numbers are in the fill up.