-- Anyone put a transmission pump to EOC ---

[trautotuning]

When my transmission is in N and with the engine off, it doesnt pump fluid through it... so I cant EOC safely.

So, with people that dont have cars with transmissions that do pump fluid while of, has anyone installed a water pump to pump fluid through it when you are EOC'ing... ??

[theholycow]

Cool idea!

Going to use an electric one, or try to run it off the output shaft?

[itjstagame]

You might look at an electric power steering pump I'm not sure what the pressure/flow requirements are but any movement would probably be enough as long as you had a tranny cooler.

[trautotuning]

So the problem when the engine is off is the tranny heating up or no fluid lubricating the tranny? or Both?

[dkjones96]

The problem isn't either of those if you are EOCing for a reasonable distance(under 20 or so miles at a time).

The only issue I have with EOC in an automatic is that you don't have any hydraulic pressure to get the transmission back into gear and you have to manually restart the engine. I'd love to be able to bump start the engine at the end of an EOC on my automatic.

In my car, as long as the engine stays above 400 or so rpm (yes, 400) it can hold a gear with the engine off but once it falls below that the transmission lets go.

[trautotuning]

So if you EOC, come to a complete stop and then restart the engine nothing would be harmed?

[Jay2TheRescue]

I think the main harm done to automatics from EOC is the fact that the insides of the transmission are spinning from the driveshaft turning, but since the pump isn't operating there's little or no lubrication.

-Jay

[dkjones96]

Most vehicles have a maximum distance they can be flat towed before the engine needs to be started and idled in neutral for a bit to relube the transmission. You should always go by this on the EOC speed and time.

The tracker manual specifies every 150 miles or 2 hours. I don't think that EOCing for a couple of miles is going to hurt my car much.

On the other hand, Saturn specs alone vary widely. Their 4 banger FWD transmissions say not to tow more than 1 mile any faster than 5mph if the front wheels are on the ground while some of their 5 speed auto 4wd vehicles can be towed at 65 mph or one hour and at the extreme end they have a few models that can be towed for 7 hours straight regardless of speed.

Check this out tho.
http://www.remcotowing.com/node/6

[theholycow]

It's my understanding that, in common automatic transmissions, they still have a high enough oil level when off to stay lubricated but without circulating that oil the heat builds up and fries the oil/transmission.

[itjstagame]

Originally Posted by theholycow

It's my understanding that, in common automatic transmissions, they still have a high enough oil level when off to stay lubricated but without [b]circulating[b] that oil the heat builds up and fries the oil/transmission.

That was always my understanding too.