Magnifico

Hello everybody,I am driving Lexus GS 300 (Europe).
I am wondering is it correctly to get in from D mode to N mode on every traffic-light or downhill or straight road because of,so-called fuel saving?I think it can damage automatic transmission but I am not sure..advance grateful for advice.

rominl

iTrader: (4)

i don't think it save any fuel, or at least it's so marginal.

but i think the main idea is safety, because there is no momentum to move forward and it's just about slope and brakes. i know in some asia region (where i come from, at least), when you do your road test, every stop, you need to throw tranny in neutral. i don't think it will hurt your tranny

worker

Well... the RPM is higher in N than in D at a dead stop. So if RPM = fuel burn than N would burn more fuel than D.

rominl

iTrader: (4)

umm, interesting question, i don't know exactly how it works. but in neutral, the load is less too i think, so i would think it's "easier" to raise the rpm. but either case, i can't see N or D making real world difference in fuel consumption (when stopped)

designo

iTrader: (6)

It is sometimes recommended to drop your gear into N at a long stop. Mainly due to gear load. But it's not absolutely necessary.

As far as fuel consumption is concerned, yes.. if your vehicle is rolling and you drop into N, your revs will fall and save fuel.

However, if you put it into D while still rolling is not a good idea. Your transmission in most cases will not match your engine speed accurately and you will hear a "clunk". If you do this frequently, you risk damaging your transmission gears.

worker

is RPM the number of revolution of the Crankshaft? And the crankshaft is push by the piston which ... fuel related. So remove the load cause the crankshaft to move faster which cause the piston to fire a little faster too... which result in a bit more fuel burning.

Anyway, stick with D. The only time I roll with N is when I don't want to start my engine down hill for a short distance.

rominl

iTrader: (4)

i don't know, but if you consider engine braking on a downhill, you use lower gear and rpm is high, but that doesn't burn more fuel. but yes, this is kind of OT.

for me i just keep it in D

mr3gs300

I usually drop it into neutral just to calm down the dreaded awd vibrations at full stop