At idle, does ATF warm faster in D or N?

[rjacket]

^^^^^^^

 

[tomcat27]

drive

 

[DutchBrad]

I have a Scanguage in the Sienna, and last night while waiting (and WAITING) for the wife at a store, I had the van running and the ATF temp got cooler while I was sitting there. Started around 130F, fell to around 110F in 20 minutes or so. At operating temp, my ATF typically runs around 100 degrees hotter than ambient temp. FYI

 

[Virtuoso]

I would think Drive, since the converter is slipping and creating heat.

 

[mechtech2]

Right - drive.
Even though the RPM are the same, there is more load with being in drive.
A minor factor, though.

 

[slammds15]

Performing stall tests on the big Allisons created some pretty insane tranny temps. I didn't realize they got that hot that quickly.

 

[HTSS_TR]

I usually shift to neutral if I have to wait more than a minute at red-light.

 

[ltslimjim]

^Good practice if this helps cool the fluid any, especially during long trips or summer stop 'n go.

 

[Shannow]

Originally Posted By: slammds15
Performing stall tests on the big Allisons created some pretty insane tranny temps. I didn't realize they got that hot that quickly.


Take a bar heater, and stick it in a couple gallons of ATF, and see how fast 1KW heats it up, let alone a couple hundred of them.

 

[1990LTD]

will the motor itself get warmer faster in D than N/P? seems like it also would with the load on it, but the same logic might not apply to engines as well as transmissions

 

[mechtech2]

The engine should warm up faster, as well. For the same reasons.
At idle, this is not a big life and death difference.

 

[TFB1]

The engine will warm more quickly in drive as there is a slight load applied, will also use additional fuel(which is mostly converted to heat) as more is required to maintain the in gear idle speed... On a carbed engine it didn't make a difference, as RPM wasn't compensated by the ECM... Since a carburetor responds to vacuum possibly it would use less in gear vs neutral/park(vac would be slightly less at the lower in gear RPM, probably have a difficult time measuring a difference though)...

Me I don't care, I'm going back in the house while the engine warms...