Transmission Heater

[Abom]

I know, the exact opposite from what everyone is trying to do, which is cool transmission fluid down. However, I am wondering, anyone had any experience with ATF when it's -40 (-41 F) degrees outside ? Does ATF gum up like engine oil does ?

I currently have an oil pan heater, which keeps the oil nice and slick. So I'm wondering if ATF would also benefit from being heated up, or does deep cold actually do good for the tranny ?

 

[BrooklynBay]

I wouldn't heat it up.

 

[BrooklynBay]

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[spindlecone]

Why Not, the guys talken -41 degs, at that temp his tranny will never see 110 when the car is running warm.

 

[BrooklynBay]

Heat is what usually helps destroy a transmission. I don't think ATF will coagulate like engine oil.

 

[spindlecone]

Heat is what usually helps destroy a transmission. I don't think ATF will coagulate like engine oil.

BB, what I am saying is, at -41 degs, the guy will never see tranny destroying temps.
I monitor my tranny temps (do you?) mine are always in the 145/170 range.
Auto trannys are made to run at certain temps, is info on the web that states that temps below 130 can be deleaterous to both the tranny, and gas mileage.
In some cases, cooler is not better.
In auto trannys,machined parts can be very finite in tolorance
I would think that keeping a tranny at say 50/60 degrees, would be optimal.
The poster lives in ultra extream conditions,JMO

 

[JDraper]

I think in those extremes, heating the tranny fluid to room temperature would be a good idea. Any time automotive seals, metals, fluids, etc. get THAT cold, it isn't good for the life of the motor.

I'd be tempted to get one of the dipstick heating elements and give it a whirl. Bringing the tranny up to room temp isn't going to hurt it in the slightest....

 

[wpurple]

I would also think that you would want to get the ATF up to running temp to burn off any condensation that accumulates.

 

[BrooklynBay]

Well there is one solution to this. You don't need a transmission block heater. If the engine has a block heater, it will keep the coolant at a specific temperature. The radiator has 2 sections, one for coolant, and one for ATF. If the coolant is already warm, then the ATF will be warm since they share the same radiator. The temperatue of the ATF will not be as warm since it is only getting warm indirectly from the thermal transfer of the radiator. A cooler that is not integrated with the radiator will not benefit in this way. It might be a good idea to have a bypass valve for the winter time on the cooler, but this valve body already has something like this built in. It's a thermal valve that cuts ATF flow to the cooler below a certain temperature.

 

[JDraper]

For the block heater to do much good, you would have to be circulating the antifreeze and the tranny fluid. Having the block warmed up doesn't mean that the radiator will warm up (yes, I understand fluid dynamics and heat transfer), and in turn warm the tranny fluid in the pan. You may get some slight residual warmth to the tranny via. the block, but since the ambient temp is -40, it will mostly bleed off to the atmosphere before doing the tranny one bit of good.

 

[WhitEngineering]

I remember a magazine article (like motortrend, car & driver??) several years back about driving in extreme cold climates such as yours and worse. The particular car they were driving (subaru i believe) had heaters all over it, transmission and engine. When your driving in -40 temps, what kind of wind chill is on your radiator at highway speeds. Your temps are never gonna get close to warm. The trans in my sierra never gets above 100 when the outside temp is below 50.

 

[BrooklynBay]

OK, so the question is to use a block heater, pan heater, or dipstick heater? The block heater would heat one specific part of the transmission, so forget about that. The pan heater might be better. The heated dipstick is probably the easiest, but then the newer transmissions like the 5R55W don't have a dipstick. The 4R55E stilln has a dipstick. Here is a picture from Glacier991's photo gallery of the valve body with the thermal valve which stops ATF flow when it's cold:

 

[Glacier991]

Depending on the tranny, the main locations of significant quantities of fluid when shut down are the pan and the torque convertor. At -40, there is some benefit to be derived at startup by warming the ATF to something warmer than -40F. But, the transmission will heat itself up pretty quick. ATF does tend to thicken like any other dino based fluid (unless you are running full syn) at colder temps.

That said, adding a pan heater, while certainly not a BAD idea, is only heating no more than maybe 40% to at most 50% of the fluid.

Is it a bad and/or harmful idea? nope. Will it be beneficial on those cold days at -40 during early warm ups - yes certainly from a performance standpoint, and to a lesser degree from a longevity standpoint. Is the different like to be significant? Probably not as much as you might think.

You will get delayed shifting longer at cold temps while the computer refuses to lock up the TC (a major heat producer unlocked, which is why it is inhibited when cold).

Overall, if you felt inclined, go for it. Mandatory? naw. (my opinion). If I had an easy to apply pan heater handy and was looking at a winter where -40 was common, would I ? Sure.

 

[Abom]

.You will get delayed shifting longer at cold temps while the computer refuses to lock up the TC (a major heat producer unlocked, which is why it is inhibited when cold).

Thank you to all who responded to this thread, reading your responses was very informative !

Glacier, I do notice this if I drive off in the morning without letting the truck warm up for a bit. I do find that if I start the truck, let it warm up for 10 or so minutes, then it's a lot easier on shifting. I currently have a block and oil pan heater. This past winter we didn't see much below -30, so I think I'm OK for now without the heater. But I have seen winters here (the past 2 of 3 years) where it's dipped down below -40 and even down below -60 one time (ice fog is fun to drive in). So I'll wait and see what happens and go from there.

I have been thinking of a circulating coolant heater, that may be my next addition.

 

[gijoecam]

Personally I don't see the need. Keep in mind, the trans uses a pretty substantial oil pump, and that pump is positive-displacement, so even if the stuff is like carmel in the morning (which isn't the case with trans fluid), it's going to pump it. -41 is nothing for trans fluid.

Now, if it's a performance question, all that pumping is going to generate heat. Pumping all that fluid through the orfices is a huge part of what generates heat (combined with friction, of course). If warmer climates take the trans fluid from 75 to 200F, wouldn't the same heat be generated taking it from -41 to 85 or so? When the ambient temp is 85 degrees and you start the truck and drive off immediately, doesn't it drive pretty normal?

Also, IIRC and if so-equipped, the bypass for the trans fluid is up on the radiator itself. It bypasses the trans fluid around the radiator if the coolant temp is too high... Stops the engine from using the transmission to cool itself. (I think I saw it on the F-series trucks though.... not on an Explorer)

-Joe

I'm of the opinion that there's no such thing as too cold for the trans fluid.

 

[aldive]

Another good reason to use synthetic ATF.

A reason, thank God, I don't need.

 

[ExploringNC]

If you had a pan heater that shuts off at a certain temp then you can do absolutly no harm. Don't think you would ever get much heat into the Torc Converter but heat does rise and would help the valve body. I've been in temps -20 to -30 below and had to take my battery in and out every time I parked the car. Everything gets really stiff and brittle so I would think the seals and o-rings in a trans are the same and you could do damage trying to use it before it reached a proper temp. Its not like he would ever overheat a tranny sitting in a driveway plugged into an outlet in those extreme temps. My question would be do they make such a heater?

 

[BrooklynBay]

The heater is not specifically for a transmission. It's an engine oil pan heater which does the same thing.

 

[Glacier991]

Actually a circulating coolant heater that warms up the radiator quickly, would assist in heating the AT, as the ATF "cooler" in the radiator coolant in this situation would act as a "heater".

 

[Abom]

Actually a circulating coolant heater that warms up the radiator quickly, would assist in heating the AT, as the ATF "cooler" in the radiator coolant in this situation would act as a "heater".

My thoughts exactly, and the heater core would be nice and toasty as well, so instant hot air coming out of the vents.