The gears in the differential & the output shaft turn whenever the car is moving, regardless of whether you're in gear or what you're doing with the clutch.

So those parts need constant lubrication - this was the area of concern in the original message.

Oh, got it. Sorry, I'm a little slow.

You do look tired!

Just kidding, but don't worry, we're all a little slow here, ;)

Yeah, don't worry about it. That's the reason I started the thread - I didn't know how it worked either.

On a rwd car disconnecting the driveshaft would prob be easy but not on a fwd car that most people tow behind stuff now. I have towed lots of cars with manual transmissions and usually the way I do it is on a rwd if the oil fill plug on the case is high enough the output shaft is getting some oil on it's gears then I don't worry about it. On a fwd car I have never bothered to check since the ring gear always slings oil when the car is moving.

It works for a briggs and stratton engine so it should work for a transmission :)

I have never towed an automatic with the engine off though. I have towed one for hours at 65mph with the engine idling and the trans in N though. I would check the manual that came with the car to find out how fast and how far you can coast with the engine off without damage. The speed is prob faster than most people here drive and the distance is much farther than you can coast before you start the engine and drive it back up to speed.

Only transmissions I have had die are a ford aod and my metro trans lost a bolt on the shifter mechanism once. So I have had pretty good luck on not blowing them up that often except on my jeep and it blows a transmission along with pretty much all of the drivetrain pretty regular.

Hi guys, I'm the one who originally sent the e-mail to MetroMPG. Lots of good info here, I hadn't thought about the fact that the diff and trans are in the same case on a FWD car. I there is a reason that you see old RWD often towed backwards so the front wheels are on the grount and you see FWD cars towed forwards so the back wheels are on the ground.

My point in the e-mail, though I didn't make it all that well, is that you don't know what kind of car the person reading has, and EOC may or may not damage that car depending on design, maybe a disclaimer would be in order.

I've been experimenting with EOC in my Fit since reading MetroMPGs experiment and the results seem to be dramatic (I had one short trip show 280 MPG because it was mostly down hill). I live in a very hilly area so things are probably magnified. I haven't gone a full tank since I started EOC so I can't really judge yet but the scanguage results look good. One interesting thing with my car though is when the engine is off the odometer doesn't read, unless I turn the key back to the on position as soon as the engine dies. Have any of you that have done a lot of EOC noticed much of a change if you EOC with the key in the on-position vs in the off position?

I have noticed though that after a long period of EOC (sometimes upwards of 2 miles) the transmission makes a whining noise after I get back into gear. Maybe the diff and output are getting lube but all of the sudden starting the gears going again after they have been still long enough for the oil to drip off is causing the noise? It goes away after a short period of normal driving.

Having fun saving fuel - Bennet

Hey Bennet - nice to see you here.

I agree with your point that there should be a disclaimer. Regular participants here know about "caveat experimentor", but you're right: I should post something to that effect with the coasting article on metrompg.com

FYI, I'd expect you will see a significant increase in mpg through EOC use. 10% is a good guess, based on my own results & those of others here.

Well I've only done one before and after on the same route, both from a cold start, and similar times of day.

The first trip with no EOC I got 34.6 on the way there and 36.7 on the way back. The second trip with a fair amount of EOC was 41.8 there and 46.4 back! That?s a 23% change! I did a little bit of pulse and glide style in there as well, and the first trips numbers are likely low because the scanguage doesn't read injector shut-off, but still that is huge.