Coasting

Volucris · May 24, 2009

Is it bad for your 4L60e transmission to coast 10 miles at 65 mph in nuetral? I've always been told it was.

Stevens03 · May 24, 2009

Thats some serious hypermiling

I don't think it would hurt anything....

ukrkoz · May 24, 2009

Is it bad for your 4L60e transmission to coast 10 miles at 65 mph in nuetral? I've always been told it was.

to coast like in being towed, or to coast like in rolling down the Alps? as 1st makes big difference on a 4x4.

as of using automatic trannie to save gas by rolling in neutral... well, if you read articles on hypermiling, they do advise to do so. i tried it once in my 2000 silvie, and i will not do it again, as when kicked back into D, trannie jumped like and old scared nule. yet, i do this for several days in 91 civic we got, and that trannie does not mind rolling down the hills in neutral at all. so, i'd say - play it by ear and common sense.

brims · May 24, 2009

Is it bad for your 4L60e transmission to coast 10 miles at 65 mph in nuetral? I've always been told it was.

to coast like in being towed, or to coast like in rolling down the Alps? as 1st makes big difference on a 4x4.

as of using automatic trannie to save gas by rolling in neutral... well, if you read articles on hypermiling, they do advise to do so. i tried it once in my 2000 silvie, and i will not do it again, as when kicked back into D, trannie jumped like and old scared nule. yet, i do this for several days in 91 civic we got, and that trannie does not mind rolling down the hills in neutral at all. so, i'd say - play it by ear and common sense.

If you rev up the engine to where it should be before you put it back in neutral, wouldn't that solve the problem?

builderpaul · May 24, 2009

Is it bad for your 4L60e transmission to coast 10 miles at 65 mph in nuetral? I've always been told it was.

Coasting is no problem as long as the engine is on.

If vehicle is towed/coasted without the engine running that is bad.

c4cruiser · May 24, 2009

I would think it would be more of a safety issue. With the trans in neutral, if you would ever have to need engine power to avoid something, it would take a few seconds for you to reach for the shifter, put the trans in gear, wait for the engine to come up to whatever RPM for the vehicle speed, and then you still have to hit the throttle to accelerate. It doesn't sound like much but even if it's only 2 seconds, the truck has traveled about 200 feet at that speed.

And with the GMT900 trucks, the azzinine torque management BS won't even let the tranny downshift immediately when you go to WOT.

With coasting going downhill, running in neutral takes away all engine braking. You would be relying completely on the vehicle brakes. Downhill coasting could very well cause enough heat from braking to see a loss of braking power either through excessive heat in the pads/rotors or getting the brake fluid so hot that it will boil which reduces braking power even further.

Airspeed-Alive · May 24, 2009

I do this all the time in my stick shift... but I've always been told to never do it with an automatic. Someone said that the power steering pump could get damaged. I need to do some research.

redvett · May 24, 2009

Aside from being illegal to not having vehicle in gear going down hill your going to use more fuel in neutral while moving. In gear the PCM knows and shuts off fuel while decelerating but in neutral will keep fueling as if it was standing still.

Volucris · May 24, 2009

to coast like in being towed, or to coast like in rolling down the Alps? as 1st makes big difference on a 4x4.

To coast as in rolling down the rockies. I70 has long stretches coming down from the divide where you can coast along from 60 to 70. I used to do it all the time when I had a standard. I was always told that doing it with an automatic will 'burn up the transmission'.

And I agree, there are some safety issue doing it. If the traffic is really light though, it's nice to do.

georgecdisc · May 24, 2009

Aside from being illegal to not having vehicle in gear going down hill your going to use more fuel in neutral while moving. In gear the PCM knows and shuts off fuel while decelerating but in neutral will keep fueling as if it was standing still.

+1

Not sure about automatics, but in my old stick shift I could feel/hear the fuel cut-off. When gas is not applied for several seconds fuel is completely cut off to the engine, resulting in 0 fuel being used. Also, when this happened the truck seemed to engine brake slightly harder. With automatics I never know what is going on when coasting down a hill, for sure there is little to zero engine braking going on, which I miss.

chuck16 · May 24, 2009

Ummm Guys, if no fuel is being used then how is the engine staying running? Wouldn't the engine shut off of if the fuel shut off????

wlvrn1215 · May 24, 2009

I don't belive it is illegal to coast in N

bobf1234 · May 24, 2009

I'll see what my Scangauge says... GPH coasting in gear and GPH in neutral.

brims · May 24, 2009

Aside from being illegal to not having vehicle in gear going down hill your going to use more fuel in neutral while moving. In gear the PCM knows and shuts off fuel while decelerating but in neutral will keep fueling as if it was standing still.

+1

Not sure about automatics, but in my old stick shift I could feel/hear the fuel cut-off. When gas is not applied for several seconds fuel is completely cut off to the engine, resulting in 0 fuel being used. Also, when this happened the truck seemed to engine brake slightly harder. With automatics I never know what is going on when coasting down a hill, for sure there is little to zero engine braking going on, which I miss.

+1 with what chuck16 said, unless you had a hybrid or turned the engine off, you were still using fuel.