Engine/Transmission (1998.5 - 2002) ATF freezing

[MCharlebois]

in the TSB it said it possible for the atf to freeze in the lines at -5f... ... ... ... it was a VERY!!!! cold winter last year-----does this just mean the TC would not lock up or was it starvin the transmission????????i know when its really cold it takes a few miles for the TC to lock up--have been very easy on her when its under 0-F-----i THOUGHT that ATF-4 was synthetic-AMSOIL just came out with ATF didn,t they

WTF over

 

[parcher]

The fact that it takes your tc longer to lock up when cold is not the fault of the fluid. This is a strategy by the controller to ge the trans to operating temp quicker. Shifts are delayed and so is lock up.

 

[Fireman Dave]

What parcher said.



I'm pretty sure ATF doesn't freeze at that temp. I'm sure it has some freeze point, but I bet it's a lot lower than -5. If it froze at that warm of a temp, there would be a lot of ruined transmissions when it gets down to -20 around here. I'll also bet that someone here knows at what temp it does freeze at.

 

[pwr2tow]

I think the point DC is trying to get across is that transmission fluid like any fluid will get thicker the colder it gets. They also might be taking into account wind chill effects, a phenomena known up here in the north that makes it significantly colder than temperature alone.



There use to be transmission problems caused by cold fluid flow in the earlier converter lockup transmissions, can not remember the years but that has been supposedly cured when they put a bypass in so the fluid will not flow to the coolers until it reaches a certain temperature. I know the later trucks such as mine and newer are suppose to have this by-pass valve. Maybe it only pertains to the gas models, don't know for sure.



Ron



EDIT::: They also might be taking into account wind chill effects, a phenomena known up here in the north that makes it significantly colder than temperature alone.

 

[amsoilman]

Freezing ATF

I hardly think that ATF is going to freeze at -5 F. The "Pour point of a "base stock" (the foundation of the lubricant) can provide insight as to the ability to function in cold temperature applications. The lower the "pour point" of a lubricant, the lower the ambient temperature at which it will still function. However, keep in mind that a significant difference exists between a fluid's pour point and its ability to be circulated (pumpability). As a rule of thumb, the lower extreme of "pumpability" is 15-20 F. higher than the fluid's pourpoint.



For example, a "PAO" Synthetic base stock has a "pour point" of

-70 F but the "pumpability" of this base stock would function down to -50 F.



Keep in mind, a PAO base stock has no paraffin wax where a mineral base stock would, and would need "pour point" depressants to help in achieving lower pour points. Also as lubricants are used, their low temperature properties deteriorate due to contamination.



Wayne

amsoilman

 

[JR2]

EDIT::: They also might be taking into account wind chill effects, a phenomena known up here in the north that makes it significantly colder than temperature alone.

Wind chill has no effect on non-living items. If its -35 outside the coldest the fluid is going to be is -35.





JR2

 

[pwr2tow]

Originally posted by JR2

Wind chill has no effect on non-living items. If its -35 outside the coldest the fluid is going to be is -35.





JR2

True, but heat dissipation is greater, the same reason we use a radiator to cool the engine.



Ron