I notice my 7AT has quite a bit of tranny drag while rolling. Sometimes this is great, little brake use - other times this uses more fuel as I have to give it gas just to get to a red light.

Is it bad for anything in the drive train if I shift to neutral when rolling up to a distant red light?

In the Dallas area I can see a red light 1-2 tenths of a mile away. If I take my foot off the gas at 45 mph, I'll be almost to a stop in less than 1/10th of a mile. If I shift to nuetral, I'll roll and roll, easily to any red light ahead. Shifting to nuetral feels like I've released my drag chute...

If the light turns green while rolling, I pop it back into D and ease on ahead.

I was warned about my 2003 Honda Pilot about shifting to nuetral when rolling. Something about a bearing in the tranny getting worn. Anyone know about the automatic G?

 

i've been doing the same thing cause I noticed the drag on the tranny when in gear...Hope I haven't been doing bad stuff to the trans.

 

On a manual tranny I wouldn't see a prob with this(except for your brakes going sooner!) but with a auto tranny I'd think downshifting into your lowest gear(engine braking) would be better than throwing it into neutral(of course at a gradual pace!)

 

But that's the problem the OP is referring to. The engine braking that occurs when you coast using the 7AT is significant (and often undesireable), and he wants to avoid it by shifting into Neutral.

To the OP: I share your dislike for this 7A behavior. My 2004 G35 (5A) had a little bit of it, but it was not nearly as pronounced. My biggest concern about shifting into neutral is the fact that you may have to shift back to D before the car comes to a stop, and this action can be somewhat abrupt (i.e., not good for the tranny). There is another general safety concern about driving in neutral - which is that you can't react as fast to manuever or get out of the way when something unplanned happens - e.g. someone moves into your lane or cuts in front, obstacle in the road, etc.

My bottom-line recommendation would be to accept the 7A behavior, use a little more gas when necessary (it's not that much), and keep your peace of mind about not damaging the tranny or not being able to avoid a simple accident because you weren't in a drive gear.

 

A little known fact about modern fuel injected cars: They use less gas coasting in gear then when put into neutral gear. That's because an idling engine always requires a small amount of fuel, but when the car is coasting in gear, no fuel in necessary and under most circumstances the fuel pulse drops to zero.

But if you have to hit the gas pedal in order to coast up to a red light, then I think that seems like an excessive amount of drag from the transmission. On a level road, my automatic transmission car will never stop while coasting. Seriously, it would just keep going forever, or at least until the road slops upwards enough to stop the car.

 

Your signature says you have a 6MT. I can assure you that the G37 7AT will come to a quick halt on a level road if you don't keep giving it gas. The behavior varies depending on what gear it's in and the initial speed, but it often feels like the brakes are being applied. Yeah, that much

 

Maybe the G has regenerative braking and nobody told us!

 

Force it out of an "eco mode" downshift by putting it into DS then keeping it at the highest possible gear for the speed you're in. It won't solve your problem, but it will help lengthen the amount of time you're in the higher gear.

 

I'm not sure what the advantage is of shifting to neutral. You actually use more gas in neutral than when coasting in gear (because the engine uses no gas at all when coasting but must use some to keep it turning over in neutral). Plus, I don't think this is good for your tranny (same reason why they tell you not to tow an automatic on the drive wheels in neutral)....

 

MSCA is referring to automatic tranny "creep" which will prevent the car from ever totally stopping while in gear, unless the brakes are applied or a hill becomes too steep. My suggestion for not having to reapply the throttle to make it to the light would be simply to wait a little longer before coming off of the throttle when approaching a red light...

 

You car will use less gas with the car in gear and in D or DS*. The computer will almost cut the fuel completely coasting in gear. As far as hurting the AT, you are putting more stress on the clutches/bands.

The drag (engine braking) with the 7AT is very nice, reminds me of driving a MT.

*My last car went in to open loop when I let off the gas and had it in gear. I don't know if the G does that. I'll have to connect my laptop to the car and run some logs when I get some free time.

 

Thanks for the advice and opinions, folks... I'll likely keep it in gear, going forward (pardon the pun!)

 

Actually, I like the so called drag which is really engine braking and your best friend if you learn how to use it. Just taking your foot off the gas slows down the G and reduces the need for unnecessary brake use. Next time you drive behind a guy that's stepping on and off the gas to keep the car paced in traffic, just thank the G engineers because your stepping on and off the gas is sufficient.

GED

 

How could the car be using less or no gas to coast when the engine is doin it's downshift flares? Conceptually, isn't the auto trans kinda doin a heel/toe downshift for you? Meaning throttle blip while down shiftin to next lower gear to preset the engine RPM up just before the lower gear engages? Other than avoidance of objects...I can't see the neutral coasting thing being that bad...Coming from a 6mt - I use to hypermill to distance redlights all the time?

 

That's kinda where I was coming from, unless there is damage to the drive train somewhere, going to N when rolling two 10ths of a mile makes sense to me. I don't see how I can use less gas leaving it in gear if I have to give it gas to travel the same distance.

But then again, any excessive wear on the drive train / tranny is not worth the pennies saved i gas!