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Old 11-23-2010, 01:40 AM   #9 (permalink)
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Quote:
Originally Posted by Angelus359 View Post

Can re-engaging the transmission from neutral, while moving, be damaging to the auto transmission? Often I'll start coast down to a light, and then before I get there, it turns green again. There are a LOT of lights around here (every 2-4 blocks on all major roads, and all side roads have stopsign every block).

I live on the southern edge of chicago.

I think maybe the temperature is coming into play a bit.
Lots of short drives. I rarely drive more than 6 miles.
I have an '09 Aveo5 and have the same stop sign and traffic lights situation as you do with the city MPG being lousy, especially for such a small car.

You might find this thread of interest: click here.

Poor city gas mileage is entirely due to the way the automatic transmission is programmed. Mine gets excellent FE on the highway (37 MPG) but only about 21-22 in the city. I bought it as a commuter car for my wife and the driving done with it is entirely city driving. Frankly, I think that GM fudged EPA stats for city MPG.

I would not recommend re-engaging the A/T from neutral into drive while moving. The car will not know what gear to go into, and probably will go into a lower gear than appropriate. I once burned out the clutches on an A/T by doing this and having a tranny rebuilt is a very expensive proposition. Go to an independent transmission repair shop and ask them this question. They will advise against it.

However, what you can do safely is to throw it into neutral and coast when approaching a stop sign. You will need to stop anyway, and when you put it back into drive it will go into first gear - which is OK as long as you are moving at less than 10 MPH.

Another strategy that helps is to accelerate briskly to get into the highest gear possible, as quickly as possible, then keep your foot off the gas as much as possible except to keep it at speed for whatever the highest gear it is in. The lower gears really consume fuel. The shift points are at about 12, 25 and 32 MPH, respectively. But the 'holy grail' magic number is 45 MPH, as that is when the torque converter locks up and the FE increases dramatically. On most cars this occurs at about 40 MPH, and Chevy really messed up in making the lockup occur so late. Unfortunately there is no way to change it. That's how they get 37 MPG highway: the speed must be more than 45 MPH. But there is no way you will get anywhere near that much in city driving, even if you are going 30 or 40 MPH.
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