Coasting????

[touringcamry]

There is fuel cut on manuals. When the accelerator is lifted, the engine is driven by the motion of the wheels and no longer needs fuel to sustain the cycles. If I let my car coast long enough or if I'm going slow enough, I can feel where the fuel comes back on to maintain a speed.

[GeneW1]

Originally Posted by 10thanntransam

I have a 2008 V6 Automatic TRD Sport. I drive 100 miles a day to work, and at night on my way home, I drive down alot of hills on the Turnpike. I place the transmission in neutral, and coast about 4 miles a night. That is 20 miles a week, which helps out the mpg, and I maintain 70-75 mph while doing this. I read a blog a few weeks ago that said that could be harmful to a transmission. Anybody have any comments about this???

Open your owners manual. If "Dinghy towing" is okay that means that your AT will tolerate being towed, and run with the engine shut off.

Dinghy towing is how those folks with RVs take a car along with them. They hitch it up to the back of the RV.

If your manual indicates that you'll damage the AT I would not do it.

Gene

[GeneW1]

Originally Posted by thaharlequin

Last I checked cars from the 70s/80s still had shaft driven oil pumps and could be pushed started. Even cars w/o 'em can be based on what I've read, but it certainly isn't recommended, just possible. Naturally vehicle speed has to be quite high compared to a manual being push started, especially when the transmission fluid is hot.

I've never met anyone who push started an AT. Among my friends were folks who rebuilt Powerglides, Turbohydramatics of all vintages including some of the crummy new ones and even a Ford AT or two.

I'm not saying that you're wrong, just that I've never heard of such a thing, push starting an AT car. I've seen folks push start MTs many times, including Motorcycles.

GM ATs from the 1960s onwards will fry if you drive them with the motor off, drive them backwards for long distances or dingy tow them. The degree of "how long" you could do it depended on the AT. I don't have practical experience with destroying ATs by towing them, driving them backwards or coasting them. I destroyed them the ld fashioned way, I wore them out.

Originally Posted by thaharlequin

Flash stall when gunning it is just as high IME so I don't see where the extra shock load is coming from. I suppose in a car with really short gearing dropping it from N to D could result in going from idle to ~3-5k rpm, but in that case the driver's biggest problem is having crappy gearing.

Every kid does "neutral drops" some time or another. Occasionally parents get stuck paying off the Transmission Man to replace "hard parts" during rebuilds.

Gene

[GeneW1]

Originally Posted by touringcamry

There is fuel cut on manuals. When the accelerator is lifted, the engine is driven by the motion of the wheels and no longer needs fuel to sustain the cycles. If I let my car coast long enough or if I'm going slow enough, I can feel where the fuel comes back on to maintain a speed.

Some ATs have that too. It's called "DFCO". If a person has a Scanguage or equivalent they can see this at work.

Gene