Neutral While Cruising?

[the_trademarc]

Just got a question guys.

I was told by a rozzer a while back that cruising in neutral (manual or auto) on a flat surface, downhill or coming to a stop is considered dangerous driving under the law, as you lose control of some braking power, as well risking warping your brakes.

However, having just completed an advanced driving course on the weekend, we were informed by the professional driving instructor that it is ok to cruise in neutral (either auto or manual) on a straight bed or coming up to a stop. He likened it to being the same as having your clutch in whilst braking.

Begs the question....for anyone with a decent mechanical knowledge.....which one is right? I'm leaning towards the driving instructor's theory because I know some cops try to talk as if they know what they're on about, but some genuinely do though.

[1SIKR8]

well .... comming up to a stop the pen pushes in the government would read to much into and notice if its in netural its taken away your engine brake ... which in smart people world ( that drive camarys ) is bad ! also the warping of brakes is the biggest load of bull#### since rud's promises .... how does it make a diffrence if its in neutral or not .. your applying the brakes ....

well thats my point of view and im a 2nd year apprentice .. so its a lil bit mechanical lol

[Ado]

No good for an auto,thats why if you flat tow an auto you should remove the tailshaft.Cant remember why off the top of my head.

[GenReaper]

You should NEVER drive a car with an auto over say 20kph in neutral or you will burn the sucker out.
A driving instructor is not a qualified auto transmission specialist so take anything he says with a pinch of salt, Manual yes you can but Auto no way.

The tranny hydraulic pump is driven by the input shaft from the torque convertor. Therefore if the output shaft is spinning at 100kph and the engine is idling it won't be delivering the required pressure to the tranny. It's the same as running your engine at 3000rpm with an oil pump delivering 1000rpm of oil pressure. The result is increased wear, burnt tranny fluid and a premature visit to the tranny shop.

[Darren_L]

from a mechanical point of view (manual transmission) no real issue. Engine braking is only really required under prelonged heavy braking eg going down a mountain range. Otherwise brakes will easily handle pulling up at a set of lights without the assistance of engine braking.

but from a driver control perspective, I reckon it's bad.
If you need to suddenly accelerate to get yourself out of situation, it's too late by the time you slot the box back into gear.

[the_trademarc]

from a mechanical point of view (manual transmission) no real issue. Engine braking is only really required under prelonged heavy braking eg going down a mountain range. Otherwise brakes will easily handle pulling up at a set of lights without the assistance of engine braking.

but from a driver control perspective, I reckon it's bad.
If you need to suddenly accelerate to get yourself out of situation, it's too late by the time you slot the box back into gear.

Fair call.
Thanks guys for the input.

Seeing as I drive a Manual, I generally downshift and and have the clutch in coming to a stop, usually just leave it in gear with CC on on a straight road. Less hassle.
But it is interesting to note that even professional instructors aren't the most mechanically minded people.