Wear and tear on automatic transmission
 

During my 50 round trip commute, I'm shifting to neutral at every stop light and also during downhill coasts. I drive a 2005 Subaru Impreza with 65,000 miles. First off, am I saving gas by shifting to neutral? Is this constant shifting causing wear and tear on my transmission?

This is my first post. I heard about hyper-milers on CNN the other day.

Welcome.

You are saving gas with your strategy. Do you have a baseline figure so you know if you've improved?

No wear comes from shifting to N, or shifting to D at a stop. I am pretty sure that almost no wear comes from doing it at speed; however, if you want, you may want to try to rev-match. This means you give it just a tiny amount of gas as you're shifting to D, just enough for the engine to rev up to the same RPM that it will be going once it's in D. In most late-model vehicles, I suspect that you'd have to be going more than 50mph to even be concerned with it, since at lower speeds your RPM in D will be close to idle.

What is your vehicle?

You might want to search our section devoted to automatics. Lots of good stuff there.

I also inflated my tires to 40 (44 maximum), rather than the 32 front/29 rear that my door jam recommends. I have get new tires soon anyway, so I decided to stay at 40. When I get the new tires, I'll put it at the maximum psi rating.

I've been doing 3 things since that CNN report: 1) drive no more than 57 mph (it seems like everyone is giving me the finger as they pass by) 2) putting in neutral whenever possible 3) increasing tire pressure.

Before all this, I was getting about 370 miles on 13 gallons. This past week, I got 402 on the same number of gallons. Not hyper-mileage, but I'll take any increase, so I'm happy.

For your Subaru run your front tires at 37-39 cold and your rears 1 psi lower. Great handling, wear, and mpg.