AT netural downhill

nepali · 03-16-2012, 12:14 PM

Quote:

Originally Posted by steve1ddd

Excuse the dumb question but i really dont know much about car engines.
I have an 09 370 with Automatic Trans.
I live up in the mountains and my trip down is all down hill. In my previous car which was a stick, i jsut coasted down in netural. is it bad to do this with an AT. Its about 20 miles and i dont have to put it back into gear but maybe 1 or 2 times brienfly? is there even a benifit to doing this (like saving gas?) I do notice i am able to build up more speed while not in gear and thus can coast longer. please advise.

What if that 1-2 times you need the gears immediately but cannot react fast enough?

harman.khinda · 03-16-2012, 12:38 PM

Quote:

Originally Posted by nepali

What if that 1-2 times you need the gears immediately but cannot react fast enough?

hypothetically - turning off your car as you cost downhill and then turning it back on at the bottom would save the most gas.

Felix 808 · 03-16-2012, 01:09 PM

Actually I am going to say it is a bad practice on a few reasons.

1. You never tow an automatic with wheels on the ground in neutral- The trans pump is not pumping vital fluid for cooling. Coasting in neutral would simulate the same conditions, causing excess heat (#1 AT destroyer).

2. Delay in power if you need to gain speed for any reason

$.02 YMMV

Zipper 104 · 07-11-2015, 02:44 AM

Quote:

Originally Posted by Felix 808

Actually I am going to say it is a bad practice on a few reasons.

1. You never tow an automatic with wheels on the ground in neutral- The trans pump is not pumping vital fluid for cooling. Coasting in neutral would simulate the same conditions, causing excess heat (#1 AT destroyer).

2. Delay in power if you need to gain speed for any reason

$.02 YMMV

Number 1 absolutely. The car must be left running if you're going to coast in neutral in an automatic.

104

fuct · 03-16-2012, 04:51 PM

Quote:

Originally Posted by harman.khinda

hypothetically - turning off your car as you cost downhill and then turning it back on at the bottom would save the most gas.

prob not. the amount of gas needed for the initial fire up might be more than the total used to coast.

but yea, dont coast in any car manual or auto. its bad for the tranny

Zipper 104 · 07-11-2015, 02:46 AM

Quote:

Originally Posted by harman.khinda

hypothetically - turning off your car as you cost downhill and then turning it back on at the bottom would save the most gas.

Yup....it'll save more gas but not money. You'll be replacing the tranny.

104

03-16-2012, 01:09 PM	#3 (permalink)
Felix 808 A True Z Fanatic Join Date: Oct 2011 Location: Camarillo, CA Posts: 1,063 Drives: 2011 PW/Grey T/S 7AT Rep Power: 2808	Actually I am going to say it is a bad practice on a few reasons. 1. You never tow an automatic with wheels on the ground in neutral- The trans pump is not pumping vital fluid for cooling. Coasting in neutral would simulate the same conditions, causing excess heat (#1 AT destroyer). 2. Delay in power if you need to gain speed for any reason $.02 YMMV __________________ Semper Fi Μολὼν λαβέ