Freewheel coasting with an automatic transmission.

[JasonG]

How fast have you done this at? 60?

[PaleMelanesian]

I do it all the time in the Odyssey with no fuss. Above 55 mph or so I do rev-match it for smoothness. All the time = multiple times every mile.

[JasonG]

The more I look at modern automatics, the more they look like manuals with a locking, viscous clutch.
Thanks, I'll try it tomorrow.

[strikes]

I know this is an older post but it is very relevant to my thoughts. I feel like I am getting hypermiling down very well. The only thing I don't do so far is the coasting aspect, mainly because I fear it might be terrible for my transmission. I drive a 2010 Civic Sedan - Automatic. Should I need to Rev match or should it do this automatically? I have gathered that if I wait a couple of seconds before accelerating after switching back into D that it should be fine with no problems. Just would like a little input before doing this. I know a lot of people coast, but does it have negative effects on the transmission? I plan on keeping this car for a very very long time and would hate to have premature transmission failure.

[pdizzleccc]

Strikes - I know this was the case for older automatic transmissions, not 100% sure about new ones, but they don't really like to be driven in neutral for long, most in neutral end up disengaging the pump for the fluid, and can over heat (info is dated, and it may be contingent on if the engine is running). Anyone else reading may be able to verify this for you. I would look for more of a lockup device with your car, many new cars actually cut fuel when you are going down hill. In my BMW when in gear and the throttle is closed there is very little if any fuel going to the engine, where as if I put it into neutral and let it idle while coasting I am using fuel. If you can lockup your torque converter while going down hill you may be able to save some.

[UFO]

Neutral is fine for most automatics if you leave the engine on. Doesn't return the FE gains as engine off of course, but I've been driving my 2001 Beetle in neutral for well over 30k miles without any changes in how the automatic works.

[cRiPpLe_rOoStEr]

I once did neutral-coasting in an automatic Corolla, with the engine off and driving downhill. No, it wasn't a suicidal attempt

[pdizzleccc]

My stepdad did a downhill coast with the engine off years ago and it overheated the transmission, he was stuck on the side of the road for quite a while.

[mcrews]

217,000 on a 1997 Toyota Avalon....always coasting in neutral engine on (automatic)
275,000 on a 2002 Infiniti Q45 always coasting in neutral engine on (automatic)
Never had a tranny problem w/ either. Did run a cooler on the Q45 but that was becuase of the front grill block.

Only car I PERSONALLY could not coast in was a late (the last swoppy oval body) model Tauras. the rpms never dropped when in neutral.

(many threads on this topic success)

[ksa8907]

Originally Posted by strikes

I know this is an older post but it is very relevant to my thoughts. I feel like I am getting hypermiling down very well. The only thing I don't do so far is the coasting aspect, mainly because I fear it might be terrible for my transmission. I drive a 2010 Civic Sedan - Automatic. Should I need to Rev match or should it do this automatically? I have gathered that if I wait a couple of seconds before accelerating after switching back into D that it should be fine with no problems. Just would like a little input before doing this. I know a lot of people coast, but does it have negative effects on the transmission? I plan on keeping this car for a very very long time and would hate to have premature transmission failure.

The only way you might cause damage is by turning the engine off while coasting in neutral.