E4OD - neutral coasting, engine on - Diesel Forum

**bigblue** · 08-04-2008, 06:15 PM

I don't ask many questions, but I have one now.

The owner's manual say that our E4OD trucks can be flat towed 35 mph/50 miles if you do this that and the other thing. I have been coasting with the engine on and the tranny in neutral to save fuel. Specifically, @60 mph, I shift to neutral then coast to 45 mph, then shift to drive, wait for the TC to lock up, then accelerate back up to 60mph. Rinse and repeat. I also coast in neutral from 60 mph, down to 35 mph or less and then brake to the stop sign. I have been doing this over the past 600 miles with no problems whatsoever.

Why am I doing this? Answer: To get 50% better fuel economy.

My question: Am I going to destroy my BTS E4OD transmission doing this?

I do understand that any comments/advice you graciously give would be followed by the [disclaimer] clause and/or off the record. Feel free to PM if you don't want your comments public. My specs are in my signature.

Thanks in advance.

chuckster57 · 08-04-2008, 06:21 PM

I'd been told for years that coasting with any automatic tranny was not good for the tranny. As I have been getting older and spending more time here I am finding some things to be old wives tales...Is this but another one

91diesel · 08-04-2008, 08:37 PM

A lot of people would scold me for this but I shut my engine down and coast for a good 1/4, or sometimes if im lucky, 1/2 mile then pop(okay, not pop) the clutch in 5th to restart. I dont know why it would be so hard on an automatic to coast. I can see it being hard when you reengage it but not while coasting.

**bigblue** · 08-05-2008, 06:39 AM

On re-engagement, all is nice and smooth - no jolting or hard shifting. It's almost like letting off the throttle in Drive, then accelerating again except without the engine compression braking effect. I do give it a little "feather" after I go into Drive, but no acceleration until the TC kicks in.

91diesel - this is what hypermilers call EOC, or Engine Off Coasting. A very common practice for increasing FE (Fuel Efficiency). Of course the main concerns are turning the key back too far locking the steering wheel, and losing brakes if you have power brakes. After a few tries you get to know how your vehicle responds and away goes those concerns. The talent part of the "pop" start is using the clutch for a near bumpless restart in 5th.

Riding with my "old-fogey" neighbor (he's like a million years old!), I noticed he was downshifting his auto transmission and using it as a trailer brake for his horse trailer. I almost jumped out of my seat. But he'd been doing it for years, and after all "wasn't that what it was for?" he said. THAT has to be far worse than anything I am doing.

Thanks for your opinions!

91diesel · 08-05-2008, 11:35 AM

Yeah im used to controlling it already. I put it in nuetral, let it get to idle then shut it off and turn key back to run so mileage registers and I can restart any time I need. Im interested to see what mileage I get with EOC, and these rebuilt injectors. I filled up today and ive got 4 miles on the ticker.

How did you get the ecomodder chart in your signature?

**bigblue** · 08-05-2008, 01:47 PM

I had to cut and paste it more or less. It's not an auto-update chart. I erased the ecomodder.com and logo because I thought I might get some flak for advertising or something. If you belong to the ecomodder, just right click the chart on the bottom of "fuel log", then "save as" a bmp. I had to open it in paintbrush to save the bmp as a jpg. Here at Diesel Stop, under User CP/signature, you can upload that jpg from your PC and add it to your signature. It won't accept bmp or the [IMG] link for autoupdating. Dang.

wetnsloppy4x · 08-05-2008, 05:39 PM

Quote:

Originally Posted by chuckster57

I'd been told for years that coasting with any automatic tranny was not good for the tranny. As I have been getting older and spending more time here I am finding some things to be old wives tales...Is this but another one

Not such an old wives tale there.

You can coast in neutral all day long without fear of damage as long as THE ENGINE IS RUNNING. If the engine is running, the trans pump is running and circulating fluid normally.

If the engine IS NOT running, the trans pump isn't turning and parts will get burned up.

I hope that helps.

chuckster57 · 08-05-2008, 05:49 PM

I guess I'll have to give it a try. Just not too many hills to coast down around here.

91diesel · 08-05-2008, 10:00 PM

putnam county ,ohio ......FLAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAATTT