Another Q, is this true?

[dham]

I got this off of a oil cooler manufacturer's FAQ's section and was wondering if this were true. I am more concerned with the first sentence rather than the rest of the answer because here in TX we hardly ever see sub-zero temps. I thought there was an optimum temperature range for the trans fluid?

Q. Can you over cool the transmission fluid?
A. Transmissions are not highly sensitive to cool operating temperatures. However, in sub-zero (20-30° F) weather conditions transmission fluid can actually gel up in an external cooler and cease to flow, causing damage. Use of the radiator cooler actually helps warm the fluid under these conditions. It is critical in extreme cold conditions to use the original equipment cooler in series with the auxiliary cooler and allow the vehicle to warm up before driving.

 

[SPITMAN]

here in the frozen north we always put an ATF by-pass valve in the external oil lines -- its job is to reroute the oil away from the cooler until the oil reaches a reasonable (180 to 200) temperature. My 89 dodge caravan was recalled in its first year of life to have such a by-pass installed.

 

[dkcase]

quote:

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Originally posted by dham:
in sub-zero (20-30° F) weather conditions transmission fluid can actually gel up in an external cooler

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You know, I saw that statement too somewhere. I wonder if they meant to say temperatures of -20 or -30. They did after all say sub-zero...

 

[dham]

I think they may have meant sub-zero in the sense that 32°F is equal to 0°C. So sub-zero in Celsius would be anything below 32°F.