NO Damage to auto transmission by EOC

[ScottC33]

I have an '07 Toyota Tundra and am getting 21-22 MPG (combined -- 85% highway driving) by using basic hypermiling techniques. The sticker said 16/20.

I'm looking to do some EOC, but WAS concerned about damage to the automatic transmission. I talked to the service department at the Toyota dealership, and the guy said I will do NO damage to the transmission by coasting with the engine off for a short period of time (ex. down a hill) or by shifting in and out of neutral.

As far as EOC goes, he agreed that, since the engine is off, the transmission isn't doing anything. There's no damage to be done.

Does anyone have any contrary information? People talk a lot, but often know very little about what they are talking about. It's really amazing. If anyone KNOWS that this information I got is wrong, by all means, speak up. I really want to try the EOC, but don't want to fry a $4,000 transmission in the process.

Thanks in advance for any input you may have.

Scott

[Daox]

Welcome to the site ScottC33.

The same rule goes for all vehicles. Check your owners manual to see if your vehicle can be flat towed or not.

Since you are moving, and your wheels are rotating, and the wheels are directly connected to parts of the transmission which are then also rotating, parts of the transmission are moving and it is possible they are not going to get lubricated properly with the engine off.

[millenniumtree]

Originally Posted by Daox

Check your owners manual to see if your vehicle can be flat towed or not.

Ding ding ding ding ding!!!
That's the best answer I've ever heard regarding this issue. Seems so obvious now. :P

[SuperTrooper]

The most comprehensive list I've seen for vehicles that CAN be flat towed is Motorhome Magazine's towing guide:

Dinghy Towing Basics

The Tundra is NOT on the list for 2007 vehicles.

[trikkonceptz]

I know only time and repair bills wil tell, but EOC vs Flat tow are to completely different subjects. Other than the extreme EOC'ers here I couldn't imagine anyone EOCing for more than a mile at a time and if they do they probably have manual tranny's.

I for one, EOC an Automatic also, the longest stretch I have EOC'd is 3/4 of a mile, I have no hills here. Therefore I have convinced myself that with synthetic oil in the tranny pan, there is enough sloshing around the tranny to keep it safe for short distances.

But again, that is an untested opinion, but if I'm wrong then I will simply switch to a manual tranny and be done with it ..

[Tourigjm]

Originally Posted by trikkonceptz

But again, that is an untested opinion, but if I'm wrong then I will simply switch to a manual tranny and be done with it ..

Same here, I don't EOC on the highway though, glides are too short.

I only EOC in town... Gotten out and pushed too

[Arminius]

I've never seen a manual say that coasting in neutral with the engine on will void a warranty. If people are concerned about EOC, they can still use neutral. It won't be quite as efficient, but it will be close. I will continue to EOC, however.

I EOC for more than a mile (1.2 miles) at least once a day.

[ATaylorRacing]

I know for a fact that Chyrsler trannies when coasting in neutral with the engine shut off can be ruined fairly quickly if coastibg at over 25 mph.....the engine must be runing for the pump to be circulating the fluid....if you see one being flat towed they have hooked up an electrical pump to not have any troubles. The longest EOC I did was about8 miles at one time....leaving Rock City.

[trikkonceptz]

Originally Posted by Arminius

I've never seen a manual say that coasting in neutral with the engine on will void a warranty.

And you won't because;
-It's impossible to prove a failure as a result of Coasting
-Until someone gets hurt doing it, sues and wins, you won't see it printed.

The best example of this is the customer who bought an RV, set the cruise control and left the wheel. Obviously crashed, then sued the RV company and won because it didn't say she had to stay behind the wheel while in cruise control. It says it now ... LOL

[atomicradish]

I used to EOC in an old Metro before it finally bit the dust. The auto tranny was crapped out and you had to shift using the gear shifter. Simply putting it in D would not work. Sometimes it would start off in 2nd gear and do 0 - 60 in about 30 seconds. Anyway, I was hoping I could kill it off for good using EOC... nope. I think EOC is fine in automatic as long as you're not coasting for extreme distances. I would be weary of distances over a mile, but distances less than that not so much. From my understanding, the transmission is not getting vital oil and lubricants during when being flat towed. Unless you're coasting for extremely long distances I doubt you would have enough time to burn up the transmission.

Of course my opinion is untested as well.... just don't come knocking on my door if your tranny bites the dust.

[Will]

Originally Posted by SuperTrooper

The most comprehensive list I've seen for vehicles that CAN be flat towed is Motorhome Magazine's towing guide:

Dinghy Towing Basics

The Tundra is NOT on the list for 2007 vehicles.

Uh is this for towing a Tundra behind an RV, or towing an RV behind a Tundra?

[jonr]

I wonder if anyone ever uses the towed vehicle to add power for accelerating? Ie, when pulling into traffic or going up a hill, the towed vehicle starts up and adds power, then shuts off the engine.

In theory, this would allow one to use a smaller more efficient engine on the towing vehicle.

[trikkonceptz]

That would be an awesome idea for RV'ers, the problem is that the dingy would have to be automatic and probably the size of a full size truck in order to move an rv from 0- whatever. I can't see a yaris making much ground on a full size bus RV ..LOL

Then of course you have 99.9 percent of all automatic tranny's can't be towed behind an RV.

[jonr]

Good point - the wheels on the towed vehicle would need a freewheel/ratchet installed - it can then push forward, but when turned off, the transmission wouldn't move.

Would be useful even if the towed vehicle was just accelerating its own weight.

[adrive7]

I tried EOCing in my 2005 Chevy Cobalt once, and despite it being on that dinghy towable list, I won't be trying it again. I was on a long down-sloping stretch of country road with nobody around, so I popped it into neutral and shut the engine off. I was rolling at about 40mph, brakes and steering felt ok, so I kept going until I got to the stop sign at the bottom of the hill. I kicked the engine back on so I had my power brakes back and came to a stop at the sign.

When I pulled away from the stop the car was acting like a manual trans. with very poor clutch work. Shifts were hard and jerky, and coming to a stop the RPMs would drop to around 500 shaking the whole car before it popped out of gear. It did this the rest of the way home. The car sat for about 30 minutes before I needed it again and the problem was gone, I think it just drained too much fluid from the torque converter, and it never got a chance to refill, or something. I don't know all that much about transmissions. It hasn't been a problem since then (3 months).

[azraelswrd]

How long did you EOC adrive? Good to hear nothing bad happened permanently.

[adrive7]

It was probably .75-1 mile tops.

[texanidiot25]

Your service manager probably wants your money when you burn up the tranny.

The tranny gets it's lubrication pumped from the spinning of the engine. When you put it in N and shut off the engine, the drive shaft is still spinning gears inside the tranny. This is why in manuals they say the car should never be towed above 25-30 mph for short distances in N with out the drive shaft pulled out.

Leaving the engine on and coasting in my '90 Firebird along with other driving style changes shot from an average 12 mpg to 20 mpg. Keep the engine on and keep cash in your pocket.

[Arminius]

You guys are freakin' me out about the EOC.

[elhigh]

I read a couple of days ago that Ford's next version of - I think it was the Fusion - will be flat-towed capable.